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'[PIC:] Olin's Easyprog'
2004\07\27@123616 by Howard Winter

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I've bought (and received) one of Olin's Easyprog PCBs ( http://www.embedinc.com/easyprog ) and I seem to have
most of the parts "in stock", but there are a couple of queries.  Since it's unsupported, I'm asking here in
case anyone can help...

The design uses 2N4401 and 2N4403 transistors, which aren't easily obtainable hereabouts.  But looking at the
specs, they are extremely similar to 2N3904 and 2N3906 - how likely is it that the latter will work, and the
former were specified just because they happened to be handy?  Or is there some obscure property of the 2N440x
that is important and that I haven't spotted?

The holes for the ZIF socket are tiny - the same size as those for resistors and such, and on all the ZIF
sockets I have the pins are much too big, and "flat" in the opposite direction to ICs, so they won't go into
the PCB or "turned pin" IC sockets at all, and conventional "flat" IC sockets are almost impossible to use
because the ZIF's pins are edge-on to the wiping contacts in the socket.  Does anyone have a favourite socket
that will accept a 3M (green) ZIF socket properly?

The board is nicely designed, with everything just about where you'd expect, and it's about the optimum
density for hand-soldering through-hole components.

Interestingly in relation to the "beginners' components" topic, I had in stock all of the capacitors, all the
semiconductors except the transistors, half of the connectors and sockets, but only five out of eleven of the
resistor values, since I tend to have the E12 series and most of these are E24.

Cheers,

Howard Winter
St.Albans, England

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2004\07\27@134338 by Kevin

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> I've bought (and received) one of Olin's Easyprog PCBs ( http://www.embedinc.com/easyprog ) and I seem to have
> most of the parts "in stock", but there are a couple of queries.  Since it's unsupported, I'm asking here in
> case anyone can help...
>
> The design uses 2N4401 and 2N4403 transistors, which aren't easily obtainable hereabouts.  But looking at the
> specs, they are extremely similar to 2N3904 and 2N3906 - how likely is it that the latter will work, and the
> former were specified just because they happened to be handy?  Or is there some obscure property of the 2N440x
> that is important and that I haven't spotted?

I am no EE, but I have heard Olin refer to the 2N440*
transistors as jelly bean transistors, as in cheap and
handy. So, I am sure that is why he used them. I think
it would be safe to substitute the 2N390* transistors you
have on hand for the 2N440* in his design.
Hopefully, one of the EEs will stop talking about
cell phones on planes and answer soon :)
Who knows, I am sure Olin might even get around to posting a
reply.

Good Luck,
       Kevin

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2004\07\27@144819 by David VanHorn

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At 11:37 AM 7/27/2004, Howard Winter wrote:

>I've bought (and received) one of Olin's Easyprog PCBs ( http://www.embedinc.com/easyprog ) and I seem to have
>most of the parts "in stock", but there are a couple of queries.  Since it's unsupported, I'm asking here in
>case anyone can help...
>
>The design uses 2N4401 and 2N4403 transistors, which aren't easily obtainable hereabouts.

3904 and 3906 are probably fine, but I have 4401 and 4403's if you're nervous.

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2004\07\27@191150 by Russell McMahon

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> The design uses 2N4401 and 2N4403 transistors, which aren't easily
obtainable hereabouts.  But looking at the
> specs, they are extremely similar to 2N3904 and 2N3906 - how likely is it
that the latter will work, and the
> former were specified just because they happened to be handy?  Or is there
some obscure property of the 2N440x
> that is important and that I haven't spotted?

If you are in UK then BC337/327 are probably available. The 337 will
substitute in almost NPN every digital application you are likely to need
and the 327 in PNP applications. It is rare for circuits to need 'special"
specs - they usually just need good enough" specs. As long as the transistor
has more than requisite max V and I ratings, Beta and Ft then odds are it
will work OK. As the 337/327 are superior to most small signal transistors
in most of these parameters they work in just about any circuit. There are
exceptions, but they will be rare and I would be surprised if Olin's
programmer is so sensitive that it can't use these.

Without looking at specs, odds are that your chosen substitutions will work
too. Ask - is voltage or current spec exceeded, does it have enough current
gain. Anything else is probably irrelevant.

       RM

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2004\07\30@182931 by Olin Lathrop

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> I've bought (and received) one of Olin's Easyprog PCBs (
> http://www.embedinc.com/easyprog ) and I seem to have most of the
> parts "in stock", but there are a couple of queries.  Since it's
> unsupported, I'm asking here in case anyone can help...

I was at the Masters conference and then took some time hiking around
Arizona and just got back.  Someone else here who lurks mentioned this
message (I had PicList mail shut off while gone) so I only saw it just now.

> The design uses 2N4401 and 2N4403 transistors, which aren't easily
> obtainable hereabouts.  But looking at the specs, they are extremely
> similar to 2N3904 and 2N3906 - how likely is it that the latter will
> work, and the former were specified just because they happened to be
> handy?  Or is there some obscure property of the 2N440x that is
> important and that I haven't spotted?

If I remember right, the main difference with your substitution transistors
is that they have only about half the current rating and a slightly higher
price, at least around here.  However, none of the transistors in the
EasyProg should be carrying current anywhere near the limit of 2N4401/4403.
I looked at this issue before and concluded that 2N3904/3906 should be
acceptable substitutes.

> The holes for the ZIF socket are tiny - the same size as those for
> resistors and such, and on all the ZIF sockets I have the pins are
> much too big, and "flat" in the opposite direction to ICs, so they
> won't go into the PCB or "turned pin" IC sockets at all, and
> conventional "flat" IC sockets are almost impossible to use because
> the ZIF's pins are edge-on to the wiping contacts in the socket.
> Does anyone have a favourite socket that will accept a 3M (green) ZIF
> socket properly?

It hadn't occurred to me that other ZIF sockets require bigger holes.  All
the standard and ZIF sockets I have here have thin enough pins to fit in
those holes, probably because that is a normal hole size to use for DIP ICs.
I'm sorry, but all I can say is that the ZIF socket called for in the bill
of materials does fit.  That turns out to be an Aries unit.

> The board is nicely designed, with everything just about where you'd
> expect, and it's about the optimum density for hand-soldering
> through-hole components.

Thanks.

> Interestingly in relation to the "beginners' components" topic, I had
> in stock all of the capacitors, all the semiconductors except the
> transistors, half of the connectors and sockets, but only five out of
> eleven of the resistor values, since I tend to have the E12 series
> and most of these are E24.

I've never heard of "E12" and "E24".  I used normal 1/4 watt 5% resistor
values, which I figured would be universally available.


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Embed Inc, embedded system specialists in Littleton Massachusetts
(978) 742-9014, http://www.embedinc.com

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2004\07\30@194234 by William Chops Westfield

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>
>> The holes for the ZIF socket are tiny - the same size as those for
>> resistors and such, and on all the ZIF sockets I have the pins are
>> much too big

Can you fit a normal socket on the board, and put your ZIF socket in
THAT?

BillW

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2004\07\30@205829 by Jinx

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> I've never heard of "E12" and "E24".  I used normal 1/4 watt 5%
> resistor values, which I figured would be universally available.

The different ranges have been around for as long as I can remember

http://www.logwell.com/tech/components/resistor_values.html

"normal 1/4W 5%" is what I'd consider general purpose E12 - 1, 1.2,
1.5, 1.8, 2.2 etc.  Intermediate E24 and beyond values for specific
voltage dividers, like the 9.1, 91, 910 you'd find on a meter input for
example

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2004\07\31@142013 by Jan-Erik Soderholm

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Olin Lathrop wrote :

> I looked at this issue before and concluded that 2N3904/3906 should be
> acceptable substitutes.

I was also loking for substitutes, but in the BCxxx line, that seems to
be more common in Europe. I don't know the 2Nxxxx line to well, but
if they are reasonable "standard", I'd guess that a standard
BCxxxC (The C types have a bit higher gain) would work.

{Quote hidden}

I have a number of 40-pin 3M/Textool ZIP's on the way
from the US to Sweden, so it's bad news if they don't fit
(easily). We'll see on monday, they are probably
at the moment at my local post office...

The 3M/Textool datasheet available from Digikey says
".012 X .030 [ 0.30 X 0.76 ]" about the pin size. The data
sheet for the Aries socket (also from Digikey) says
"0.019 +/- 0.002 [0.48 +/- 0.05]. So there is a
difference...

However, the 3M/Textool sockets seems to be pretty popular
(and the only brand available on eBay at the moment... :-) ).

> > The board is nicely designed, with everything just about where you'd
> > expect, and it's about the optimum density for hand-soldering
> > through-hole components.

Agree !

> Thanks.
>
> > Interestingly in relation to the "beginners' components"
> > topic, I had in stock all of the capacitors, all the semiconductors
> > except the transistors, half of the connectors and sockets, but
> > only five out of eleven of the resistor values, since I tend to have
> > the E12 series and most of these are E24.

Three of the values (62, 300 and 430) are only available from
the E24 series. One of the values (2K) are available from the
E24 series or higher (E96 or E192).
The rest are available from the "lower" E-series (E12).

Now, many "resistor packs" available are using
values from the E12 series (incl those I have, of course :-) ).

And, if a design uses *both* 270 ohms (an E12 value) and
300 ohms (an E24 only value) in the same design, I'd expect that
there is a specific reason to do so. If not, it could just as well
have used values from the E12 series only. In particular if
it's ment to be a device "intended for hobby and prototyping use",
as the web page says.


> I've never heard of "E12" and "E24"...

Is not that numbering system used everywhere ?

http://www.logwell.com/tech/components/resistor_values.html

Best Regards,
Jan-Erik.

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2004\07\31@191455 by Bob Barr

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On Sat, 31 Jul 2004 20:20:04 +0200, Jan-Erik Soderholm wrote:

(Apologies if I've misattributed this to Olin)
>Olin Lathrop wrote :
>
>> I've never heard of "E12" and "E24"...
>
>Is not that numbering system used everywhere ?
>
>http://www.logwell.com/tech/components/resistor_values.html
>

That's the first place that I've ever seen that "E" series of numbers
used to indicate different precisions of resistors. I've been working
in electronics so long that I've been accused of having worked as an
intern for Volta. :=)

Could this "E" convention perhaps be more commonly used in Europe than
in the U.S.?


Regards, Bob

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2004\07\31@214330 by Jan-Erik Soderholm

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Bob Barr wrote :

> (Apologies if I've misattributed this to Olin)
> >Olin Lathrop wrote :
> >
> >> I've never heard of "E12" and "E24"...
> >
> >Is not that numbering system used everywhere ?
> >
> >www.logwell.com/tech/components/resistor_values.html
> >
>
> That's the first place that I've ever seen that "E" series of numbers
> used to indicate different precisions of resistors.

Yes, that's a bit confusing, they are not *directly* connected and are
not normaly specified that way.

But on the other hand, there would be no reason to produce 5% resistors
according to the E96 or E192 series, would there ? A number of
values would be overlapping within the tolerance limits.

And the absolutly highest (or lowest ?) tolerance resistors
(that is, with a very low %) are often not made according to
any of these tables, but in some "decade" (10, 20, 50, 100...) series.

> Could this "E" convention perhaps be more commonly used in Europe than
> in the U.S.?

Possibly, together with the "meter", the "kilogram" and other things
that makes life easy for everyone :-) :-)

But, seriously, it would surprice me a lot if not the resistors as sold
in the US, are according to the E-series numbering scheme.

Take one resistor pack at Digikey as an example.
The RS2X-ND, called "KIT RESISTOR 100-976 96 VALUES".
96 different values in one decade (100 ohms to 976 ohms), that's
obviously the E96 series, which is logical since this kit has 1%
metal film resistors.

Anyway, there is no reason, generaly, to use values from a "higher"
E-series, if a value from a lower series would work just as well.
It just makes it harder for anyone to find the "right" values...


Best Regards,
Jan-Erik.

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2004\07\31@231859 by Dwayne Reid

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At 05:13 PM 7/31/2004, Bob Barr wrote:
> >
> >> I've never heard of "E12" and "E24"...

This stuff was covered in school many years ago.

E3 series  1, 2.2, 4.7
E6 series  1, 1.5, 2.2, 3.3, 4.7, 6.8
E12 series 1, 1.2, 1.5, 1.8, 2.2, 2.7  etc
E24 series 1, 1.1, 1.2, 1.3, 1.5, 1.6, 1.8, 2.0, 2.2 etc

E6 was 20% tolerance series in the real old days.
E12 was 10% tolerance series
E24 was 5% tolerance series

I try to design with mostly E3 series resistor values where possible.  If
those won't work, then try to fit in E6 series, then E12, E24, E96.  In
other words, E96 values are last resort and used only where necessary.

This maximizes the chances of some poor field tech being able to quickly
get a broken piece of equipment working again with the parts he has on hand
or can get locally.

Notice that common capacitor values follow the E3 series values.

dwayne

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2004\07\31@233351 by Russell McMahon

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TUTORIAL

Summary of one point: Design where possible to use E12 series or less unless
your design demands higher precision.

> >> I've never heard of "E12" and "E24"...
> >Is not that numbering system used everywhere ?
> That's the first place that I've ever seen that "E" series of numbers
> used to indicate different precisions of resistors. I've been working
> in electronics so long that I've been accused of having worked as an
> intern for Volta. :=)

This ramble may be worth following for people wanting to design things with
resistors.
It starts off talking about WHY a series eg E12 exists, and ends up talking
about what resistors you should probably spec for your project.

FIRST - here's an excellent table showing all values in E6/12/24/48/96 & 192
ranges and their relationships
Recommended that people have a look if not familiar with the ranges.

   http://www.logwell.com/tech/components/resistor_values.html  <- ***
EXCELLENT ***

An Exx  series is  one whose xx members are distributed geometrically
symmetrically across a decade.

ie for resistors Rn+1 = Rn x K
       where K = 10^(1/xx)
For E12 series K = 1.21 (see below) so if R1 = 1k
then R2 = 1.2K
R3 = 1.21 x 1.21 = 1.468k = 1.5k
R4 = 1.21^3 = 1.778k = 1.8K etc

Far easier to use than conceptualise :-)

The point is that the relationship between the resistance of members M steps
apart is always the same to within the precision of the series.

So E12 = 1.0 1.2 1.5 1.8 2.2 2.7 3.3 3.9 4.7 5.6 6.8 8.2 (10 ...)

10^/(1/12) ~= 1.211528 ~=  1.2

Example. Take any 2 values 4 steps apart
eg  1.2 and 2.7
2.7/1.2 = 2.25
Now try again
eg 2.2 and 4.7
4.7/2.2 = 2.136 = 2.2

Slight difference in ratios due to rounding of values in standard series.
________

So you'd expect each value to increase by a factor of about 1.2 times.
And it does
For this series to be useful the variation in a given value caused by
manufacturing and operating variations shouldn't allow it to assume a value
which may reasonably be assumed by an adjacent member. This means that if
each member is 1.2 x the prior one then a step of about sqrt(1.2) will bring
you to the boundary between the neighbours. sqrt(1.2) = 1.095. Each value
could be about +/-10% before impinging on the others space.
In the good old days where resistors were quite imprecise unless especial
care was taken to make them otherwise, E12 series were indeed usually +/-
10% values. The resistors of a given value spread across this error range
and by selecting you could get almost any resistor value at all. How stable
it was with voltage, temperature time etc was another matter.

With time the standard accepted E12 resistor tolerance came to be 5%.
Even with 5% accuracy E12 values cluster as "islands" around the nominal
value. If you want a 1.1k resistor you may have to test a lot of 5% 1K0 or
1K2 resistors. Ongoing process improvements make such resistors increasingly
well defined unless you buy double flying horse brand or equivalent. Using
resistors of unknown parentage is asking for other unexpected problems. They
may only cost a cent or so each in bulk, but there is still a lot of
technology in there.

With increasing accuracy you can fit more resistor values in a decade
without overlapping.
The E96 series can fit in 96 resistors between eg 1K and 10K. The stepping
ratio K is  10^(1/96) or 1.024 so you'd expect that E96 resistors would
usually be 1% tolerance or better so that values don't overlap.

Note, you can still specify E12 values and use 1% components.
You may want 1k or 1.0k or 1.00k or even 1.000k
The precisions implied by the above figures are +/- 500r !!!! (1k)
+/- 50r (1.0k), +/15r and +/- 0.5 r
or 50%, 5%, 0.5% and 0.05%
These would be About E2, E24, E240 and E2400 ranges, *should such exist.*
Buying and using E2400 resistors would be extremely hard ! ;-)

The standard "off the shelf' resistor ranges available everywhere are E12.

   The much loved 1.0   1.2   1.5   1.8   2.2   2.7   3.3   3.9   4.7   5.6
6.8   8.2

Even if you NEED 1% values you can still specify eg 1k8 1%.
In most circuits involving microprocessors you don't NEED such accuracy.
The exceptions usually occur when you are sitting or measuring analog
levels.
eg if you use an LM317 to provide 5.0V for your processor you probably want
the 5.0V to be as accurate as the LM317 can provide. The LM317 has an
internal uncorrected reference accuracy of the order of +/- 4%. If you set
the voltage divider to scale its nominal 1.25v value up to 5v and you use 5%
components then you will probably degrade the accuracy of the resultant
voltage. HOWEVER the required ratio of the voltage setting resistors is
ABOUT 3:1. In practice it's very slightly on the low side of 3:1 due to
technical considerations (see LM317 datasheet).
With E12 resistors we are locked into ratios which are of the form  1.21^N:1
where N is the number of steps apart.
1.21^6 = 3.16.   1.21^5 = 2.61
Both are less accurate than we'd like.
In this case use of a resistor from a higher  series would help.
Using the chart at
   http://www.logwell.com/tech/components/resistor_values.html

we see that the E24 series contains a 3.00 k value.
E24 is notionally at least 100/24/2 = 2% accuracy.
In practice 1 1K 1% and a 3K 1% would be just fine.

Importantly - not that on the E24 range the 100 value and 300 value are 11
steps apart.
ANY two values on the E24 range which are 11 steps apart will have a 3:1
resistance ratio.

Now lets look at transistor base driving from a PIC.
A BC337 has a beta of 300 say at 100 mA.
So we need about 100/300 = 0.333 mA base drive
PIC output is 5v nominal so we need about a (5-0.6)/0.333 MA = 13.2K drive
resistor.

An E92 13k2 would work just fine .
**** STOP *********** Don't you dare !!!!!

An E12 10K would work just fine too.
Or an 8k2 or a 6k8 even.
A bit much current won't hurt unless things are really tight. (In which case
the above "design: was way too rough and should have been done using worst
case values - but that's another story).

TRY to design using E1 values wherever possible !!!!!!!!!!!!!!!!
ie E1 = 1k, 10k, 100k, 1m etc.
90% + of simple digital design can be done with E1 ! ;-)

Next use E2 = 1 3.3 10 33 100

E4 =  1 1.8 3.3 5.6 10 18 ....

This is perhaps quite intuitive and we MAY feel more comfortable with eg 1
3.3 6.8 10 etc
Whatever. Try to minimise values used unless essential.
Use percentage accuracy that suits.
Spec E96 or whatever as essential
Even when you need 1% tolerance, try to stick to E12 values where possible.
It often is.

Sometimes the "precision" of a desired voltage level etc may attract you to
E96 values. Always ask - is this precision necessary?. If you are doing it
for yourself and have the parts then maybe it's an OK choice. If it's for
production then the precision may allow you wider tolerances elsewhere and
it may be justified. If it's going to be used by others who have limited
access to more exotic parts then try really hard to avoid such choices.



       Russell McMahon

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2004\07\31@234559 by William Chops Westfield

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On Jul 31, 2004, at 8:17 PM, Dwayne Reid wrote:

>> >> I've never heard of "E12" and "E24"...
>
> This stuff was covered in school many years ago.
>
> E3 series  1, 2.2, 4.7
>
I assume I'm like everyone else; I knew there were standard "values"
for resistors, and I knew they were related in obvious ways to the
precision, but I just had never heard of the "E" designations...

BillW

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'[PIC:] Olin's Easyprog'
2004\08\01@022836 by Charles Craft
picon face
You're working with only half the pieces.
The 3M Zif parts come in a socket (with handle) and receptable that goes in the circuit board.


http://tinyurl.com/4rau9
Textool 3M Zif receptacle diagram at Digikey

http://dkc3.digikey.com/PDF/T042/0284.pdf
Digikey catalog page showing Textool 3M components

http://tinyurl.com/5blkn
3M site on Zif sockets

{Quote hidden}

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2004\08\01@044939 by Howard Winter

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Olin,

On Fri, 30 Jul 2004 18:29:36 -0400, Olin Lathrop wrote:

> > I've bought (and received) one of Olin's Easyprog PCBs (
> > http://www.embedinc.com/easyprog ) and I seem to have most of the
> > parts "in stock", but there are a couple of queries.  Since it's
> > unsupported, I'm asking here in case anyone can help...
>
> I was at the Masters conference and then took some time hiking around
> Arizona and just got back.  Someone else here who lurks mentioned this
> message (I had PicList mail shut off while gone) so I only saw it just now.

Thanks for the reply - I wasn't necessarily expecting one!  :-)

2N4401 and 2N4403 transistors vs. 2N3904 and 2N3906...

> If I remember right, the main difference with your substitution transistors
> is that they have only about half the current rating and a slightly higher
> price, at least around here.

Well price isn't an issue here - it's availability.  Getting "your" transistors means mailorder from over
there as against a 10-minute drive to my local Maplin, except that I have "my" transistors in stock already
anyway!  :-)  You're right on the current - 200 vs. 600mA, and the gain curve is higher with "yours", peaking
at 150mA vs. 10mA for a gain of 100.

> However, none of the transistors in the
> EasyProg should be carrying current anywhere near the limit of 2N4401/4403.
> I looked at this issue before and concluded that 2N3904/3906 should be
> acceptable substitutes.

Great - thanks!

{Quote hidden}

Right - I don't know if they are available here - pretty-much everyone sells the 3M ones (including Digi-key
over there, I see), and they have the annoyingly-wide pins.  I just measured one and they are 0.9mm wide,
0.45mm thick, giving a diagonal a tad over 1mm.  As far as I can measure your holes for P1 are 0.95mm
(interestingly, the 5 holes for ICSP are about 1.3mm and accept the ZIF pins easily).   So anyway it looks
like I'll need to place an order with Jameco after all!

> > The board is nicely designed, with everything just about where you'd
> > expect, and it's about the optimum density for hand-soldering
> > through-hole components.
>
> Thanks.

Credit where it's due!  :-)  I also like the way you've left gaps at the corners for stick-on feet.  Even
Microchip get this wrong - on their PICkit1 (for 8 and 14-pin PICS) they have feet stuck over holes that are
supposed to be used for components and the 9-pin D socket on the breadboard section.

> > Interestingly in relation to the "beginners' components" topic, I had
> > in stock all of the capacitors, all the semiconductors except the
> > transistors, half of the connectors and sockets, but only five out of
> > eleven of the resistor values, since I tend to have the E12 series
> > and most of these are E24.
>
> I've never heard of "E12" and "E24".  I used normal 1/4 watt 5% resistor
> values, which I figured would be universally available.

OK, I don't know if the "E" stands for Europe - but I don't think so.  The E-series are "preferred" resistor
values, with the number indicating the number of values per decade...
E3 is: 10 22 and 47 (and all the decades from 1.0 to 10M, obviously)
E6 fills in between with: 15 33 and 68
E12 adds: 12 18 27 39 56 and 82 and finally
E24 also has: 11 13 16 20 24 30 36 43 51 62 75 and 91

The idea being that values in the lower ranges are more likely to be used (and more likely to be available),
and packs of resistors usually consist of everything in one series (E12 is very popular, giving 72 values from
10R to 820K).  I have a good stock of E12 values, but very few that are E24-only.  Obviously in a well-stocked
workshop such as yours you'd have pretty-much everything, so it's not obvious which values us hobby types will
tend not to have!  :-)

Thanks for your help - as it looks like I'll be ordering the ZIF socket from Jameco I may as well get the
correct transistors as well so there shouldn't be any issues there.

Cheers,

Howard Winter
St.Albans, England

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2004\08\01@045355 by Howard Winter

face
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Bill,

On Fri, 30 Jul 2004 16:41:33 -0700, William Chops Westfield wrote:

> >> The holes for the ZIF socket are tiny - the same size as those for
> >> resistors and such, and on all the ZIF sockets I have the pins are
> >> much too big
>
> Can you fit a normal socket on the board, and put your ZIF socket in
> THAT?

I'd love to, but I can't find an IC socket that will accept the ZIF socket pins - they are too big for
turned-pin sockets and the wrong way round for dual-wipe sockets - they are wide across the socket rather than
along it, as with ICs, and it just won't go in.  Unless you know of some that will work?

Cheers,



Howard Winter
St.Albans, England

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2004\08\01@045811 by Howard Winter

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Jinx,

On Sat, 31 Jul 2004 12:58:44 +1200, Jinx wrote:

>...<
> The different ranges have been around for as long as I
can remember
>
>
www.logwell.com/tech/components/resistor_values.h
tml

Thanks for the reference - I wish I'd read ahead on the
thread before replying to Olin - would have saved me
waffling on about it myself  :-)

And my "you learn something new every day" item for
today is that the E-series go as far as E192!

Cheers,


Howard Winter
St.Albans, England

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2004\08\01@054037 by Howard Winter

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Charles,

On Sun, 1 Aug 2004 02:28:22 -0400, Charles Craft wrote:

> You're working with only half the pieces.
> The 3M Zif parts come in a socket (with handle) and
receptable that goes in the circuit board.

I've never seen that receptacle before - and certainly
never seen it for sale over here.

> http://dkc3.digikey.com/PDF/T042/0284.pdf
> Digikey catalog page showing Textool 3M components

Good grief, so as well as paying $35 for the socket you
have to pay $22 to plug it in???  I think I'll buy the
one Olin specified from Jameco for $11.25!

Cheers,


Howard Winter
St.Albans, England

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2004\08\01@055944 by Howard Winter

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Jan-Erik,

On Sat, 31 Jul 2004 20:20:04 +0200, Jan-Erik Soderholm wrote:

> Olin Lathrop wrote :
>
> > I looked at this issue before and concluded that 2N3904/3906 should be
> > acceptable substitutes.
>
> I was also loking for substitutes, but in the BCxxx line, that seems to
> be more common in Europe. I don't know the 2Nxxxx line to well, but
> if they are reasonable "standard", I'd guess that a standard
> BCxxxC (The C types have a bit higher gain) would work.

I think the BC337 and BC327 look pretty close, and with a slightly higher voltage capability.

>...<
> I have a number of 40-pin 3M/Textool ZIP's on the way
> from the US to Sweden, so it's bad news if they don't fit
> (easily). We'll see on monday, they are probably
> at the moment at my local post office...
>
> The 3M/Textool datasheet available from Digikey says
> ".012 X .030 [ 0.30 X 0.76 ]" about the pin size.

If that's for the actual 3M ZIF's pins, and not the receptacle that Charles mentioned, then those measurements
are wrong for the ones I have.  I've just measured a number of them and they all seem to be around 0.018" x
0.035" [ 0.44mm x 0.9mm ]

> The data
> sheet for the Aries socket (also from Digikey) says
> "0.019 +/- 0.002 [0.48 +/- 0.05]. So there is a
> difference...

Presumably a round pin, since only one dimension is given.  One of the problems with the 3M is that the pins
are rectangular, which makes it awkward in a round hole.

> However, the 3M/Textool sockets seems to be pretty popular
> (and the only brand available on eBay at the moment... :-) ).

Quite - that's where I get most of mine!  :-)  The others come from Amateur Radio rallies.

Cheers,



Howard Winter
St.Albans, England

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2004\08\01@062057 by Howard Winter

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Bill,

On Sat, 31 Jul 2004 20:46:46 -0700, William Chops Westfield wrote:

>...<
> I assume I'm like everyone else;

That's funny - I've always assumed I'm different from everyone else!  :-)

> I knew there were standard "values"
> for resistors, and I knew they were related in obvious ways to the
> precision, but I just had never heard of the "E" designations...

I think I learned this at about the same time I found out which end of a soldering iron gets hot (and it was a
much less painful lesson! :-)  I think it was the second thing I learned about resistors, just after the fact
that resistance *isn't* useless in a circuit that's more complex than battery-switch-bulb.  I wonder why
knowledge of this is so patchy?

I never learned electronics formally, mostly from magazines like Practical Electronics, which did "beginners"
tutorials which taught everything from the basics.  Unfortunately they didn't do that middle bit in between
transistors being used in their "normal" mode to amplify the signal at the Base (I forget: is this emitter
follower?) and all the other ways of using them, and reasons for doing so.  Consequently my knowledge of
analog electronics stagnated and I am *much* happier with digital!

Cheers,

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2004\08\01@065952 by Jan-Erik Soderholm

face picon face
Howard Winter wrote :

> E3 is: 10 22 and 47 (and all the decades from 1.0 to 10M, obviously)
> E6 fills in between with: 15 33 and 68
> E12 adds: 12 18 27 39 56 and 82 and finally
> E24 also has: 11 13 16 20 24 30 36 43 51 62 75 and 91

Hi.
Not a big deal, but...

Note that higher E-series do not "add" values or "fills in" any values.
Many values from lower series are actualy replaced.
Some values are only available in a single series, like the
300 resistor in the EasyProg (hey ! back on-topic !! :-) )
that's only available from the E24 series but not in either
any lower *or* higher series.


Jan-Erik.

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2004\08\01@083500 by Wouter van Ooijen

face picon face
> I'd love to, but I can't find an IC socket that will accept
> the ZIF socket pins - they are too big for
> turned-pin sockets and the wrong way round for dual-wipe
> sockets - they are wide across the socket rather than
> along it, as with ICs, and it just won't go in.  Unless you
> know of some that will work?

In a similar situation I took a round-pin socket, put the ZIF on top of
it (indeed, you can not insert the flat pins of the ZIF) and soldered
the ZIF pins into the cups of the socket. Put a dual-wipe in the PCB and
you will be able to take out your expensive ZIF if you want to use it
for another purpose.

Wouter van Ooijen

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2004\08\01@103748 by Olin Lathrop

face picon face
Jan-Erik Soderholm wrote:
> And, if a design uses *both* 270 ohms (an E12 value) and
> 300 ohms (an E24 only value) in the same design, I'd expect that
> there is a specific reason to do so.

Not necessarily in this case.  This discussion is the first I heard of "E"
series designations for resistors.  I had always considered the standard 1/4
watt 5% resistor series to be universally available.  From the link you
sent, that would be the E24 series.  I used values from that series without
any consideration about whether they would be available in a sparser series.

5% 1/4 watt resistors are the base line in most catalogs.  All places that I
know of that sell these resistors sell all the E24 values.  Since any of
these values are available for $.99 per bag of 100 from Jameco, I didn't
think that would be a problem.

Doesn't Jameco (http://www.jameco.com) ship outside the US?  Resistors are
small and light weight, so the extra shipping shouldn't be much especially
if you buy a few other things (like the ZIF socket).  That's why I included
Jameco part numbers on the bill of materials for any non-generic parts.

If someone really wants to splurge, they can get 100 of all the 1/4 watt 5%
values from 2.2 ohms to 10Mohms for $120.  That should fix the problem for a
long time and facilitate general hobby projects.

I just checked, and the two 300 ohm resistors (R21, R22) are used in voltage
dividers that effect the target chip Vdd values.  I do not recommend
substituting a different value.


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2004\08\01@105239 by Olin Lathrop

face picon face
Dwayne Reid wrote:
> This stuff was covered in school many years ago.
>
> E3 series  1, 2.2, 4.7
> E6 series  1, 1.5, 2.2, 3.3, 4.7, 6.8
> E12 series 1, 1.2, 1.5, 1.8, 2.2, 2.7  etc
> E24 series 1, 1.1, 1.2, 1.3, 1.5, 1.6, 1.8, 2.0, 2.2 etc
>
> E6 was 20% tolerance series in the real old days.
> E12 was 10% tolerance series
> E24 was 5% tolerance series

Yes I was aware of these series, just never heard of the "E" names for them
before.  However, since 5% resistors are really the low end today, I'm
surprised that E6 and E12 are still considered more available than E24.

I still remember the days of 1/2 watt and 1 watt resistors with silver
stripes (10%) soldered point to point between the bottoms of tube sockets.
However, I wouldn't even know where to buy 10% resistors today, and I doubt
there would be any cost savings over 5% even if I did find them.

So why isn't E24 considered the "baseline" today even by hobbyists?
Seriously, I'm asking, since this issue caught me completely by surprise and
I still don't see a good reason behind it.


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2004\08\01@105655 by Olin Lathrop

face picon face
Russell McMahon wrote:
> The point is that the relationship between the resistance of members
> M steps apart is always the same to within the precision of the
> series.

Yes, I understand why the series are what they are.  What I don't understand
is why E12 is still considered more available than E24 since 10% resistors
have gone the way of dinosours a long time ago.


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2004\08\01@110732 by Jan-Erik Soderholm

face picon face
Olin Lathrop wrote :

> Russell McMahon wrote:
> > The point is that the relationship between the resistance of members
> > M steps apart is always the same to within the precision of the
> > series.
>
> Yes, I understand why the series are what they are.  What I
> don't understand is why E12 is still considered more available
> than E24 since 10% resistors have gone the way of dinosours
> a long time ago.

First, don't mix up the value series with the precision, they
are two different things.

Second, most/many "resistor packs" are using the E12 (or
close to it) values, even if they contain 5% carbon film resistors.
Se Jameco # 10719CL :
"5 ea. 70 values (every other value from 10.- 5.6 M.) (350 pcs.)"
This pack cost $9.95 each.

"Every other" in this case, does not include the 300 resistor.

Then there are the $119.95 pack with all values, but at
a slightly higher cost :-)

10% resistor have nothing to do with this, that was just
bad writing on that otherwise fine web page...

Jan-Erik.

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2004\08\01@112432 by Olin Lathrop

face picon face
Charles Craft wrote:
> You're working with only half the pieces.
> The 3M Zif parts come in a socket (with handle) and receptable that
> goes in the circuit board.

Yes, there are lots of different ZIF sockets out there.  I didn't try to
design a board that would accept them all, nor did I claim that it would.  I
did specify a particular ZIF socket in the bill of materials.

As with any substitutions not listed in the BOM, you're taking a risk.  You
have to make sure you know what the relevant specifications are and that the
substituted part will meet them.  If you're not sure, you can try asking
here.  If you're still not sure, stick to the specified parts.

To minimize someone getting caught by this in the future, I have added a
note about the ZIF socket specs to the BOM at
http://www.embedinc.com/easyprog/prog7_bom.txt.htm.


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2004\08\01@113925 by Olin Lathrop

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Howard Winter wrote:
> Right - I don't know if they are available here - pretty-much
> everyone sells the 3M ones (including Digi-key over there, I see),
> and they have the annoyingly-wide pins.  I just measured one and they
> are 0.9mm wide,
> 0.45mm thick, giving a diagonal a tad over 1mm.  As far as I can
> measure your holes for P1 are 0.95mm

The holes for the ZIF socket are specified as .029 inch in Eagle.  Allowing
for .004" tolerance from the PC house leaves .025" (about .64mm) max pin
diameter for a sure fit.

> (interestingly, the 5 holes for
> ICSP are about 1.3mm and accept the ZIF pins easily).

That size hole with .1" pitch doesn't allow for traces between the holes.
That's not a big deal for 5 pads, but I don't know what it would have done
to the routing if 2 rows of 20 pins were blocking both layers from pass thru
traces, not to mention the large break in the "ground plane" top layer.

One reason I like these ZIF sockets is that the pad footprint is the same as
a normal 40 pin DIP IC.  In other words, this single footprint can accept a
ZIF socket, a normal 40 pin DIP socket, or a 40 pin IC, and still allow one
trace or ground layer to run between each set of adjacent pads.


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2004\08\01@130741 by Howard Winter

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Olin,

On Sun, 1 Aug 2004 10:53:22 -0400, Olin Lathrop wrote:

>...<
> So why isn't E24 considered the "baseline" today even by hobbyists?
> Seriously, I'm asking, since this issue caught me completely by surprise and
> I still don't see a good reason behind it.

Sheer numbers, I think.  My favourite electronics supplier, Maplin, sell an E12 set for £7.99 which has 10
each of 61 values, and an E24 set for £19.99 which has 133 values, it costs more than twice as much, and the
extra values are the little-used ones, so the law of diminishing returns applies.  Added to which you need
more than twice the storage space - twice as many little drawers or trays or whatever you use to store the
darned things, and even 61 values is a bit of a space-hog.

I already have plenty of the E12 set and for 95% of projects it's good enough.

To build the Easyprog I could either buy the 1330 resistor pack, and probably never use 1,000 of them, or buy
the less-than-20 individuals that I haven't got in stock... per resistor the latter is more expensive but it's
the way I'll go!

Cheers,


Howard Winter
St.Albans, England

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2004\08\01@134141 by Wouter van Ooijen

face picon face
> Yes, I understand why the series are what they are.  What I
> don't understand
> is why E12 is still considered more available than E24 since
> 10% resistors
> have gone the way of dinosours a long time ago.

When you try to limit the number of different components you have in
stock it makes sense to stick to a (lower) E serie and stock all values
in that serie. Hence when you design for DIY it makes sense to limit
yourself to the lowest (reasonable!) E serie.

Wouter van Ooijen

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2004\08\01@181141 by Jan-Erik Soderholm

face picon face
Charles Craft wrote :

> You're working with only half the pieces.
> The 3M Zif parts come in a socket (with handle) and
> receptable that goes in the circuit board.

Hi.
I'm a bit lost here...

I've looked at the links below and and I can clearly see the
second part of the 3M Textool ZIP socket (the "receptacles").

Now, when looking at two major electronic distributors in
Sweden (ELFA and Farnell), both has the 3M Textool sockets,
but neither of them has the "receptacles"...

Farnell also has the 40-pin "Aries" ZIP socket @ aprox
$25 USD (excl the 25% Swedish VAT). The "universal" 40-pin
3M Textool socket cost $55 each (excl VAT). I got them
for $4 each from eBay (a batch of 50) b.t.w...

Well well, I'll wait for the package and see what I'll do
about it.

Jan-Erik.


> http://tinyurl.com/4rau9
> Textool 3M Zif receptacle diagram at Digikey
>
> http://dkc3.digikey.com/PDF/T042/0284.pdf
> Digikey catalog page showing Textool 3M components
>
> http://tinyurl.com/5blkn
> 3M site on Zif sockets
>

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2004\08\01@182422 by Josh Koffman

face picon face
I don't know specifically about these sockets, but you might be able
to just modify the pins. The board house we use for prototypes, and
the one we use for production take the hole sizes in the file to be
different things. One uses it as final size, the other uses it as
drill size. A couple of times I've had to sand down some headers
because they were a few thou too big for a hole. I used a Dremel with
a sanding disk. Be careful, as they will remove material at a rapid
rate. You also might want to glue the socket to the board so you won't
be relying on the now thinned pins for mechanical connection.

Josh
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On Mon, 2 Aug 2004 00:10:57 +0200, Jan-Erik Soderholm
<.....jan-erik.soderholmKILLspamspam@spam@telia.com> wrote:
> Well well, I'll wait for the package and see what I'll do
> about it.

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2004\08\01@183706 by Olin Lathrop

face picon face
Jan-Erik Soderholm wrote:
> Farnell also has the 40-pin "Aries" ZIP socket @ aprox
> $25 USD (excl the 25% Swedish VAT). The "universal" 40-pin
> 3M Textool socket cost $55 each (excl VAT). I got them
> for $4 each from eBay (a batch of 50) b.t.w...
>
> Well well, I'll wait for the package and see what I'll do
> about it.

I assume your ZIF sockets have two rows of 20 pins with .1" pin pitch and
6" between the rows.  If so, maybe you can make your socket pins sit on top
of the holes and solder them onto the tops of the pads.  This probably
depends on how long the pins are, how far the socket overhangs, and how thin
your soldering iron is.  Each connection won't be that strong, but all 40
together should be good enough.


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2004\08\01@213620 by dpmohne

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face
Russell,

       Thank you very much for this tutorial, it is awsome.

Duane


On Sun, 1 Aug 2004, Russell McMahon wrote:

{Quote hidden}

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2004\08\01@215110 by Jim Robertson

flavicon
face
>The holes for the ZIF socket are tiny - the same size as those for
>resistors and such, and on all the ZIF
>sockets I have the pins are much too big, and "flat" in the opposite
>direction to ICs, so they won't go into
>the PCB or "turned pin" IC sockets at all, and conventional "flat" IC
>sockets are almost impossible to use
>because the ZIF's pins are edge-on to the wiping contacts in the
>socket.  Does anyone have a favourite socket
>that will accept a 3M (green) ZIF socket properly?


Have a look here:

http://www.dontronics.com/hints.html#sockets

and maybe here:

http://www.dontronics.com/hints.html#pins

Olin, you may want to consider altering your hole sizes on the next PCB
revision
to accept the larger ZIF pin size.

I have used at least five different brands of ZIF sockets and of these only
the ARIES brand had the thin pins. All other brands use the wide pins.

Some of these other brands of ZIF socket are not only much easier to
operate than
the ARIES ZIF, they also can be very much less expensive and easier to get
in some parts of the world.

Regards,

Jim Robertson
NEWFOUND ELECTRONICS

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2004\08\02@041350 by Alan B. Pearce

face picon face
> That's the first place that I've ever seen that "E" series of numbers
> used to indicate different precisions of resistors.

It may be a more common designation in Europe, but the number indicates the
number of values in a decade, i.e. the E12 series has 12 values in a decade,
which fits using 10% resistors, (and for many years was the only set of
values you could obtain, even with 5% resistors being the norm), and the E24
has 24 values in the decade.

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2004\08\02@043842 by Alan B. Pearce

face picon face
>Yes I was aware of these series, just never heard of the
>"E" names for them before.  However, since 5% resistors
>are really the low end today, I'm surprised that E6 and
>E12 are still considered more available than E24.

Not necessarily more available, but a manufacturer may buy larger quantities
of these value ranges as they tend to be the generic "wet finger in the air"
values to start from, and hence get used as general pull-ups in digital
circuits, and generic feedback values around opamps and the like.

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2004\08\02@045542 by Alan B. Pearce

face picon face
>The board house we use for prototypes, and the one we
>use for production take the hole sizes in the file to
>be different things. One uses it as final size, the
>other uses it as drill size.

And you don't specify which you want? We always specify the hole sizes to be
"after plating" with a size tolerance. The hole size needs to be set to
guarantee that the pin will go into the smallest possible "after plating"
hole from the tolerance setting. It is then up to the board house to drill
the appropriate size hole.

If the prototype house uses the hole size as the drill size, for cheapness,
then I would have thought it was up to them to use a slightly larger
standard size, with suitable agreement with yourselves, as the hole may then
be over the upper tolerance. Certainly be easier to deal with than having to
attack component leads. But if they also do production work (even if not for
you) I would have thought they would be purchasing the slightly oversize
drills needed to guarantee the hole accuracy, in sufficient quantities that
the cost difference would be minimal, compared to standard size drills.

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2004\08\02@080753 by Olin Lathrop

face picon face
Jim Robertson wrote:
> Olin, you may want to consider altering your hole sizes on the next
> PCB revision
> to accept the larger ZIF pin size.

I have a fairly large number of boards already in stock because of the way
PCB production pricing works.  I could have ordered fewer, but I would have
paid nearly the same amount.

I will look at it if I ever get an opportunity to redo the layout.  The only
potential issue is that the larger holes will prevent routing traces between
the pins.  This will make fairly large breaks in the top layer pseudo ground
plane, but that's probably not a big deal.  There should be plenty of room
on the board for a routing solution, I'm just not sure it will be one I
like.

> Some of these other brands of ZIF socket are not only much easier to
> operate than
> the ARIES ZIF, they also can be very much less expensive and easier
> to get in some parts of the world.

Hmm.  When I started this project I deliberately looked around at ZIF
sockets, and the Aries thru Jameco was well priced.  I had assumed (perhaps
incorrectly) that Jameco ships internationally, and therefore anything they
sell would be accessible to hobbyists around the world.  They are probably
the premier hobby electronics supplier here in the US.

How much to you pay for ZIF sockets down under, and where do you get them?


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2004\08\02@112557 by Jim Robertson

flavicon
face
>Jim Robertson wrote:
> > Olin, you may want to consider altering your hole sizes on the next
> > PCB revision
> > to accept the larger ZIF pin size.
>
>I have a fairly large number of boards already in stock because of the way
>PCB production pricing works.  I could have ordered fewer, but I would have
>paid nearly the same amount.
>
>I will look at it if I ever get an opportunity to redo the layout.  The only
>potential issue is that the larger holes will prevent routing traces between
>the pins.

snip...

Actually no, this will not be the case. With the length of the ZIF running
North/South, the wide side
of the rectangular pins will be running East/West across the ZIF.

From a East/West side on view, the width of the pin is pretty much the
same as the ARIES brand
and therefore your pad need be no wider in this axis. Your pad to pad
clearance is not reduced.

I am using 120 x 62 mil "rounded rectangular" pads with a 35 mil hole size.
I have  24 instances
per PCB of 12 mil tracks running between pins and 1000s of these PCBs have
been produced
without problem (all hand soldered.)



{Quote hidden}

Jameco are good for international orders and I used to buy my ZIFs from
them until I found
much (much!) cheaper sources in Asia.  I am not saying that buying a ARIES
type ZIF from
Jameco is not a reasonable solution and your homework is quite valid and
the results
are "good."


However, based on my experience it is certain that some potential Easyprog
buyers
will find they can get some other brand of ZIF easier and cheaper.  If a
future PCB
revision could accommodate the wider spade pins then buyers would have the
choice of any brand of universal ZIF as the ARIES type can still be
soldered ok into a
pad with a 35mil hold.



>How much to you pay for ZIF sockets down under, and where do you get them?
>

One of my Asian customers was able to source a very good quality ZIF for
under $3 USD
in bulk. They appear to be genuine 3M brand and are gold flashed. These are
the best
ZIFs I have come across. Because I was paying ~$3USD I am a little
concerned with some
of the prices that have been quoted in this thread.

Futurlec appear to be selling something similar looking for $9USD retail.

http://www.futurlec.com/Sockets/ZIFU40.shtml

I actually got a few samples from them but these were not gold flashed and
were stiff to open
and close like the ARIES brand.

Anyway, my point would be to consider all this next PCB revision as there
is an
opportunity to turn a "good" ZIF solution into a "better" ZIF solution.
This is not a
nit-picky suggestion


Regards,

Jim


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2004\08\02@114255 by Josh Koffman

face picon face
Well, two things here. Our proto house (Alberta Printed Circuits) has
a limited drill selection for proto service. And second, normally
we're fine... I was refering to the few times I managed to forget and
screwed up a few holes!

:)

Josh
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A common mistake that people make when trying to design something
completely foolproof is to underestimate the ingenuity of complete
fools.
       -Douglas Adams

On Mon, 2 Aug 2004 09:58:04 +0100, Alan B. Pearce <KILLspama.b.pearceKILLspamspamrl.ac.uk> wrote:
{Quote hidden}

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2004\08\02@115331 by Alan B. Pearce

face picon face
>And second, normally we're fine... I was refering to the
>few times I managed to forget and screwed up a few holes!

You really must fix that keyboard actuator :))))))))))

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'[PIC:] Olin's Easyprog'
2004\11\08@031350 by Jan-Erik Soderholm
face picon face
Hi !
Just looked through the BOM for the EasyProg again, and
noticed that the date "Last updated 4 June 2004" had changed
into "Last updated 1 Aug 2004" since I downloaded it last time.

The only difference I can see is the addition of an warning
"Beware of subsitutions..." at the ZIP socket, right ?
No other changes, as far as I can see.

/Jan-Erik.
____________________________________________

2004\11\08@075416 by olin_piclist

face picon face
Jan-Erik Soderholm wrote:
> Just looked through the BOM for the EasyProg again, and
> noticed that the date "Last updated 4 June 2004" had changed
> into "Last updated 1 Aug 2004" since I downloaded it last time.
>
> The only difference I can see is the addition of an warning
> "Beware of subsitutions..." at the ZIP socket, right ?
> No other changes, as far as I can see.

Yes, there were no functional changes.  I added the warning after I heard
that some people here bought incompatible ZIF sockets.


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2004\11\08@095105 by Dave Lag

picon face
The 16F628A  is the only A part supported ?
Any timeline for the (IIRC) block programmed devices?
D

At 07:54 AM 11/8/04, you wrote:
{Quote hidden}

____________________________________________

2004\11\08@115956 by olin_piclist

face picon face
Dave Lag wrote:
> The 16F628A  is the only A part supported ?

Also the 16F627A and the 16F648A.

> Any timeline for the (IIRC) block programmed devices?

Which PICs specifically do you mean?  I will have to look at the programming
spec and see how different it is from what is already supported.


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2004\11\09@215343 by Dave Lag

picon face

I guess the ones that come to mind are the 16F87xA
16F877A/876A/874A/873A
(these have an exclusive engagement on the samples stage;)
programming:
ww1.microchip.com/downloads/en/DeviceDoc/39589b.pdf
2.4.2.7 Begin Erase/Program Cycle
"Eight locations must be loaded before every 'Begin Erase/Programming'
command." etc
D

At 12:00 PM 11/8/04, you wrote:
>Dave Lag wrote:
> > The 16F628A  is the only A part supported ?
>Also the 16F627A and the 16F648A.
> > Any timeline for the (IIRC) block programmed devices?
>Which PICs specifically do you mean?  I will have to look at the programming
>spec and see how different it is from what is already supported.
>*****************************************************************
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____________________________________________

2004\11\10@080638 by olin_piclist

face picon face
Dave Lag wrote:
> I guess the ones that come to mind are the 16F87xA
> 16F877A/876A/874A/873A
> (these have an exclusive engagement on the samples stage;)
> programming:
> ww1.microchip.com/downloads/en/DeviceDoc/39589b.pdf
> 2.4.2.7 Begin Erase/Program Cycle
> "Eight locations must be loaded before every 'Begin Erase/Programming'
> command." etc

Those are main stream chips reasonable to support in a hobby programmer.
I'll look into the programming spec.


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____________________________________________

2004\11\10@134106 by Bob J

picon face
Olin, just out of curiousity, who makes your Easyprog pcb?  It looks top-notch.

Regards,
Bob
____________________________________________

2004\11\10@143124 by olin_piclist

face picon face
Bob J wrote:
> Olin, just out of curiousity, who makes your Easyprog pcb?  It looks
> top-notch.

Most of them were made by E-Teknet in Arizona (http://www.e-teknet.com).
They actually front end a factory in China.  I was also very pleased with
the quality.


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