Searching \ for '[OT]: Semiconductor tester [was Competitions]' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/index.htm?key=
Search entire site for: 'Semiconductor tester [was Competitions]'.

Exact match. Not showing close matches.
PICList Thread
'[OT]: Semiconductor tester [was Competitions]'
2001\04\11@150713 by Dan Michaels

flavicon
face
Roman Black wrote:
>Maybe as another suggestion for a competition
>idea, what about a universal semiconductor tester?
>Like three leads, A,B,C, and a 2-line LCD display.
>You can clip it on any transistor or diode and
>it tells which leg is which, NPN, PNP, fet,
>darlington, etc etc, even measures beta and
>saturation drop. All these things would be easy
>to measure if you could adjust voltages and measure
>voltages, say with a 16F876 or even a F628.
>Just an idea. Hey, i'd like one!!


Hey, Roman, I'll tell you what my idea is, and maybe you can tell
me what is wrong with it :).

I have been mulling this over for several months - even before
that UK company started selling exactly what you mention above.
My device would work with the little virtual instruments I have
been producing, so it relies on a PC for control/display, rather
than having its own LCD. This does make it easier to extend to
different devices, since all you have to do is change the PC
s.w. rather than the PIC firmware..

The plan is to have it work symmetrically on 3 pins, and
automatically identify transistor C, B, E, etc, as the first step,
then go on to test and identify the type of device. Should work
with BJTs, FETs, SCRs, diodes, etc.

The key is to use 6 pins in groups of 2 for different stim and
record regimens. This is purely digital, but with more complex
circuitry could be made more sophisticated. The current design
was made to be easily added to an existing device. It would not
work with zeners > 5v.

 PIC
-------+
      |                                   D.U.T.
  RB7 +-----3.3K----+-------> A ------------+
      |             |                       |
  RB6 +-----330-----+                       |
      |                                  | /  e
  RB5 +-----3.3K----+-------> B ---------|
      |             |                 b  | \  c
  RB4 +-----330-----+                       |
      |                                     |
  RB3 +-----3.3K----+-------> C ------------+
      |             |
  RB2 +-----330-----+
      |
-------+

The D.U.T. connects at A, B, C. The 330 R's are in my existing device,
but could be eliminated in a dedicated device. Basically, you use
pins RB2-RB7 as either outputs hi/lo, or as inputs for sensing.
Of each pair, normally one will sense while the other stimulates.
Flipping the pins in a pair changes the level of stimulation.

To test diode action between A and B, set RB7=out_hi, RB6=in_sense,
RB4=out_lo, RB5=in_sense. For diode conduction A->B, both RB6/RB5
will read low. By doing the inverse to that just described, you can
show no conduction in the reverse direction.

You go thru this regime for all pin combinations, discover you
have back-to-back diodes, and it's a PNP with the base at B.
Discovering whether A or C is the emitter/collector takes a
dynamic measurement.

By connecting 3 A/D channels to points A/B/C, and also possibly
using 3 more digital pins with 33K R's, you can measure more
complicated parameters, like beta, etc.

There are probably many improvements that can be made to this basic
idea. Of course, you could go whole hog and do curve tracing/etc.

best regards,
- dan michaels
http://www.oricomtech.com
=======================

--
http://www.piclist.com hint: To leave the PICList
spam_OUTpiclist-unsubscribe-requestTakeThisOuTspammitvma.mit.edu


2001\04\12@015433 by Vasile Surducan

flavicon
face
In my opinion HOW to do this is very interesting, but the result
is a toy. I can't imagine who will use this tool. Here every
child know to handle with a digital multimeter and find quickly what have
in his hands, a npn, a pnp or a fet...
And a digital multimeter is cheapest than a pic based tool ( even 12c509 )
and can do more things.
Just a thought.
Vasile

On Wed, 11 Apr 2001, Dan Michaels wrote:

{Quote hidden}

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\04\12@023501 by Antonio L Benci

flavicon
picon face
part 1 1774 bytes content-type:text/plain; charset=us-ascii (decoded 7bit)

Farnell carry such a device  in their catalog, item code 888-3310, Atlas
Component Analyser.

Vasile Surducan wrote:
{Quote hidden}

Nino.
--
------------------------------------------------------
| Antonio (Nino) L. Benci                            |
| Professional Officer, Electronic Services          |
| School of Physics & Materials Engineering          |
| Monash University                                  |
| email: nino.bencispamKILLspamspme.monash.edu                  |
| T: 61 3 9905 3649. F: 61 3 9905 3637               |
| M: 0414 924 833                                    |
------------------------------------------------------


part 2 586 bytes content-type:text/x-vcard; name=Nino.Benci.vcf; charset=us-ascii
(decoded 7bit)

begin:vcard
n:Benci;Antonio L
tel;cell:0414 924 833
tel;fax:+61 3 9905 3637
tel;home:0414 924 833
tel;work:+61 3 9905 3649
x-mozilla-html:FALSE
url:http://www.physics.monash.edu.au/~ninob
org:Monash University;School of Physics & Materials Engineering
version:2.1
email;internet:.....Nino.BenciKILLspamspam.....spme.monash.edu
title:Professional Officer, Electronic Services
adr;quoted-printable:;;PO Box 27=0D=0ASchool of Physics and Materials Engineering=0D=0AMonash University;Monash University;VIC;3800;Australia
x-mozilla-cpt:;10672
fn:Antonio L Benci
end:vcard


part 3 154 bytes
--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\04\12@055233 by Peter L. Peres

picon face
Dan, your scheme will work to determine some components, but it will not
do much curve tracing, and will not be able to fire some thyristors and
triacs. Using software PWM and two coil boosters on the 'E' and 'C' pins
will get you nearer but the metering scheme will become more complex and
would require an AD. A two channel SMPSU in boost config. controlled by
the PIC (which would have AD) would be a more appropriate idea imho. It's
a good idea for low cost testers though.

Peter

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\04\12@085555 by Roman Black

flavicon
face
Vasile Surducan wrote:
>
> In my opinion HOW to do this is very interesting, but the result
> is a toy. I can't imagine who will use this tool. Here every
> child know to handle with a digital multimeter and find quickly what have
> in his hands, a npn, a pnp or a fet...
> And a digital multimeter is cheapest than a pic based tool ( even 12c509 )
> and can do more things.
> Just a thought.
> Vasile

As a repairer of electronics goods this would be very
handy. Yes, I can use a multimeter but it would be nice to
see beta and Vce sat in the same test, as I have boxes of
older transistors etc that I often use for hobby or
prototyping.

In-circuit testing is great, my good Fluke 12 (favorite of
repairmen) does great in-circuit testing of diode junctions.

Also it should have three terminal "pads" on top, so if
you have a big box of parts you could just press each one
on to the pads and read type, beta, sat, etc. Surely this
would be handy?? :o)
-Roman

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\04\12@090914 by Roman Black

flavicon
face
Dan Michaels wrote:
{Quote hidden}

Hi Dan, yes I think that is a good start, but you really
need analogue inputs to make this work well. Also it would
be nice to have analogue outputs... TI make some quad D-A
converters at 10 bit and 12 bit, not too expensive.

I think I would prefer to have a 15vdc supply, and be able
to adjust this via the DACs. Then measure the result via
the ADC inputs. Could use 2x 9v batteries to make it portable.

Your procedure seems good, to check for obvious diode
junctions first, then explore the possible variations.
Testing Vsat well would maybe require a larger current
source, I like to test stuff at 500mA or 1A etc. I'm not
sure how this would be handled or even if it is necessary.
:o)
-Roman

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\04\12@104437 by Dan Michaels

flavicon
face
Vasile wrote:
>In my opinion HOW to do this is very interesting, but the result
>is a toy. I can't imagine who will use this tool. Here every
>child know to handle with a digital multimeter and find quickly what have
>in his hands, a npn, a pnp or a fet...
>And a digital multimeter is cheapest than a pic based tool ( even 12c509 )
>and can do more things.
>

Can you easily identify a MOSFET or SCR with a DMM, or do a
dynamic check on a semi device?

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\04\12@105102 by Dan Michaels

flavicon
face
Peter Peres wrote:
>Dan, your scheme will work to determine some components, but it will not
>do much curve tracing, and will not be able to fire some thyristors and
>triacs. Using software PWM and two coil boosters on the 'E' and 'C' pins
>will get you nearer but the metering scheme will become more complex and
>would require an AD. A two channel SMPSU in boost config. controlled by
>the PIC (which would have AD) would be a more appropriate idea imho. It's
>a good idea for low cost testers though.
>

Yeah, as indicated this wasn't really meant to be a complete curve
tracer. But part of the idea was to be able to identify which pin is
which without having a manual handy - with your scheme you already have
to know which is E and C. I also realized with only 5v available, you
cannot handle hi-V zeners or hi-I SCRs.

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\04\12@111814 by Dan Michaels

flavicon
face
Roman Black wrote:

{Quote hidden}

Hi Roman, a full-blown device tester would be nicer, as this
one is a little light on the dynamic testing end of things.

Unfortunately, it appears to be somewhat difficult to be able to
place a 3-pin part willy-nilly into a 3-pin socket and be able to
do perfectly symmetrical measurements on all pins - then you need
a switcher to be able to connect your analog input/etc to each pin
as required, once the pins have been ID'ed - got any ideas of how
to do this easily?

A PIC73 does have 3 A/D channels you could connect to points A/B/C.
Also has 2 PWM channels which could gen analog signals, and then
maybe a 3rd PWM in s.w. Maybe a clever re-assignment of the pins
rather than use portB.
============


>I think I would prefer to have a 15vdc supply, and be able
>to adjust this via the DACs. Then measure the result via
>the ADC inputs. Could use 2x 9v batteries to make it portable.
>

Yeah, 15v would be nice. But now to make everything symmetrical
you need some hi-V pin drivers that can function as both input
and outputs, plus a switching matrix for all the pins. Small
wonder those universal testers cost so much.
================


>Your procedure seems good, to check for obvious diode
>junctions first, then explore the possible variations.
>Testing Vsat well would maybe require a larger current
>source, I like to test stuff at 500mA or 1A etc. I'm not
>sure how this would be handled or even if it is necessary.

What on earth are you testing here that you need to run
500mA thru the junction. Certainly not Vbe[sat] of a BJT.
Maybe Vce[sat]? Rectifier diode?


best regards,
- dan michaels
http://www.oricomtech.com
========================

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\04\12@160335 by Dwayne Reid

flavicon
face
At 10:44 AM 4/12/01 -0400, Dan Michaels wrote:
>Vasile wrote:
> >In my opinion HOW to do this is very interesting, but the result
> >is a toy. I can't imagine who will use this tool. Here every
> >child know to handle with a digital multimeter and find quickly what have
> >in his hands, a npn, a pnp or a fet...
> >And a digital multimeter is cheapest than a pic based tool ( even 12c509 )
> >and can do more things.
> >
>
>Can you easily identify a MOSFET or SCR with a DMM, or do a
>dynamic check on a semi device?

MOSFET - easy to do.  Here is how I do it:

Set meter to diode test mode.

Moisten fingertip slightly, touch all 3 leads together.  You want to remove
any residual gate charge.

Touch meter leads to S & D backwards (+ to S for a N channel device).  If
you don't know if it is a N or P channel device, this test will tell
you.  You should see a normal Si diode drop (0.6V or so) in the reverse
direction.  This is the internal substrate diode.  If no reading either
direction, either you are on the gate terminal or the device is open.  Very
low reading in both directions: FET is shorted.

Now hold or clip the appropriate meter lead to the S lead (normal
mode).  In other words, if you have a N channel FET, clip the - lead to the
source.  Touch the + lead to D.  You should see no conduction.  Now lift
the + lead from D, touch it to G, then touch and hold the + lead on D
again.  You should now see conduction, with very low voltage
drop.  Continue to hold the leads on the FET to see if the voltage drop
changes: this gives a good idea of how good the gate insulation is.

The 1st step of the test weeds out shorted FETs quickly as well as
identifying the polarity.  It will also help you identify the leads (S,G,
D) if you are not sure.

The 2nd step of the test makes sure that the FET is really off, then uses
the open circuit voltage from the meter to apply charge to the gate (which
looks like a capacitor), then checks to make sure the charge turned on the
FET.  It also identifies FETs with defective gate insulation (the gate
charge leaks away quickly).

It takes longer to read this than to actually do the test.  I've taught
this to many broadcast engineers over the years to help them test the
output FETs in AM broadcast transmitters.  It does provide a very quick GO
- NO GO test!

dwayne



Dwayne Reid   <EraseMEdwaynerspam_OUTspamTakeThisOuTplanet.eon.net>
Trinity Electronics Systems Ltd    Edmonton, AB, CANADA
(780) 489-3199 voice          (780) 487-6397 fax

Celebrating 17 years of Engineering Innovation (1984 - 2001)

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Do NOT send unsolicited commercial email to this email address.
This message neither grants consent to receive unsolicited
commercial email nor is intended to solicit commercial email.

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\04\13@041150 by Roman Black

flavicon
face
Dwayne Reid wrote:

{Quote hidden}

Excellent info Dwayne, thanks! :o)
-Roman

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics


2001\04\13@120917 by Dan Michaels

flavicon
face
Roman wrote:
>Dwayne Reid wrote:
>
>> >Can you easily identify a MOSFET or SCR with a DMM, or do a
>> >dynamic check on a semi device?
>>
>> MOSFET - easy to do.  Here is how I do it:
.........
>> It takes longer to read this than to actually do the test.  I've taught
>> this to many broadcast engineers over the years to help them test the
>> output FETs in AM broadcast transmitters.  It does provide a very quick GO
>> - NO GO test!
>
>
>Excellent info Dwayne, thanks! :o)
>-Roman
>

Dwayne - can you go ahead and publish the corresponding routines for
NPNs, PNPs, p- and n-chan JFETs, plus various diodes, and SCR's, etc,
etc, too - so I can more easily write the corresponding routines into
my automated tester?

Just kidding :).
- dan michaels
http://www.oricomtech.com
========================

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics


More... (looser matching)
- Last day of these posts
- In 2001 , 2002 only
- Today
- New search...