Searching \ for '[EE] Need a cheap power supply' 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/power/actodc.htm?key=power
Search entire site for: 'Need a cheap power supply'.

Exact match. Not showing close matches.
PICList Thread
'[EE] Need a cheap power supply'
2012\02\11@161517 by Nathan House

picon face
I'm burning through batteries like nobody's business and think it's
high time I purchased a power supply. I know I can make my own board
with voltage regulators for common voltages like 3.3, 5, 12, etc, but
I think I'd rather have something that's adjustable and can source a
lot of current in case I ever need it. I've been looking at power
supplies on ebay and stumbled across a very low price one that seems
to be pretty popular (the seller has sold 159 of them):

http://www.ebay.com/itm/Precision-Lab-PS305D-Variable-30V-5A-DC-Power-Supply-/120716204084?pt=LH_DefaultDomain_0&hash=item1c1b3f1834

I've never heard of the brand before. What do you think, good buy or not?

Thanks,

Nate

-- Student Hobbyist
http://www.roboticsguy.co

2012\02\11@164429 by David VanHorn

picon face
I would buy it.

Don't expect miracles, but it's probably a very nice unit.
30V is a good useful range

2012\02\11@164450 by Jesse Lackey

flavicon
face
I recently bought one of these...
30V, 3A, constant-current, "mini", for $50
<www.mpja.com/0-30V-0-3A-Mini-Bench-Supply/productinfo/9615+PS/>
....but have not used it yet.

The 5 amp version, $70.
<http://www.mpja.com/0-30V0-5A-Mini-Bench-Supply/productinfo/9617+PS/>

A current-limited power supply is vital for electronics work.  If you know your circuit should draw say 200mA, you can set the current limit to 500mA, and if you hit it, then something is wrong and you get a chance to debug before you smoke your board.

Cheers
J



Nathan House wrote:
{Quote hidden}

2012\02\11@165456 by David VanHorn

picon face
The PS305D has an adjustable current limit

2012\02\11@173648 by Carl Denk

flavicon
face
IYahooed the model number "PS305D", and the first link I clicked on:

http://www.alibaba.com/product-gs/276480283/PS305D_DC_Power_Supply_Linear_mode_.html

I see a big USA on the Ebay page, but it appears obvious it's a Chinese product. A year ago, I ordered a set of Rayban sunglasses from a place in Seattle, thinking they would get shipped from Seattle. hey were shipped from China, they weren't anywhere near delivering in a month. I checked the street address on Google map, and found it was the office of the main Seattle newspaper. I canceled the order, refused the USA post shipment, and eventually  got my money back. I would check the actual shipping address, and that  USA seems very misleading, and if they are untruthfully about that, do you want to do business with them??


Might check this. I have done buisness with them several times, with good problems.

On 2/11/2012 4:15 PM, Nathan House wrote:
{Quote hidden}

>

2012\02\11@174104 by PICdude

flavicon
face
"USA brand", "USA product", etc all still does not mean made in the  US, but seems like significant marketing to cover up that it's  (probably) made in China.  No prob with China, but stuff like this  worries me.



Quoting Nathan House <spam_OUTnathanpiclistTakeThisOuTspamgmail.com>:

{Quote hidden}

>

2012\02\11@174542 by PICdude

flavicon
face
BGmicro.com also has one I was looking at recently, but IIRC it was  around $85 for 3A and only 0-15A, so this seems to be a better deal on  the surface.



Quoting Jesse Lackey <.....jsl-mlKILLspamspam@spam@celestialaudio.com>:

{Quote hidden}

>

2012\02\11@184145 by peter green

flavicon
face
Nathan House wrote:
> I'm burning through batteries like nobody's business and think it's
> high time I purchased a power supply. I know I can make my own board
> with voltage regulators for common voltages like 3.3, 5, 12, etc, but
> I think I'd rather have something that's adjustable and can source a
> lot of current in case I ever need it. I've been looking at power
> supplies on ebay and stumbled across a very low price one that seems
> to be pretty popular (the seller has sold 159 of them):
>
> http://www.ebay.com/itm/Precision-Lab-PS305D-Variable-30V-5A-DC-Power-Supply-/120716204084?pt=LH_DefaultDomain_0&hash=item1c1b3f1834
>
> I've never heard of the brand before. What do you think, good buy or not?
>   Note how they say "USA brand" but they are careful to avoid saying anything about where it was made  I'm pretty damn sure it's a chinese import and the "direct from the manufacturer" statement is probablly severely stretching the truth.

I have bought some rapid own brand PSUs that have a similar style (not sure if it's the same manufacturer or just ones buying their power buttons and banana sockets from the same place) and they seem to work ok though the meter switches can be a bit dodgy sometimes and I had one (I've bought several identical ones) lose regulation on one output (rapid replaced the unit but it's a worrying failure mode).

For the price it's probablly reasonable, I just wouldn't hook it up to anything expensive without putting some protection in between (minimum a fuse/polyswitch and a zener diode). Having said that  I would not generally reccomend using any variable PSU to power circuits directly on a long term basis. Too much risk of it getting set wrong. Put a modernish LDO with a reasonablly high allowed input voltage (I like ths LM2940 for this) on your board, run it from 6V and if someone does put too much voltage in it will just go into overheat shutdown

2012\02\12@090504 by Mark Hanchey

flavicon
face
On 2/11/2012 4:15 PM, Nathan House wrote:
> I'm burning through batteries like nobody's business and think it's
> high time I purchased a power supply. I know I can make my own board
> with voltage regulators for common voltages like 3.3, 5, 12, etc, but
> I think I'd rather have something that's adjustable and can source a
> lot of current in case I ever need it.
>
> Thanks,
>
> Nate
>

I realize you are looking for something pre-built but I have found a LM317, pot,  transformer, bridge and some caps was the way to go and if you want high current you can add a pass transistor and do it all for way cheaper than anything you will find online.  Completely adjustable , mine goes from 1.6 to 18, current can be whatever you need. You can also do negative voltages easily which cost a lot more if you buy a pre-built supply.

What I did is get a center tapped transformer and it is connected to several regulators  a 3.3, 5, 12V and it also connects to a 317T and transistor , so on the supply I have 3.3,5,12v,-5v,-12v, 1.6-18V variable and I can use them all at the same time if I want. I connected them to a barrier strip to make it easy.

Mark

2012\02\12@123130 by Peter Loron

flavicon
face
If you are willing to do a bit of hacking and are willing to settle for some fixed outputs, then you can get a ATX power supply from a computer and hack in some banana jacks for the 3.3, 5, and 12V outputs. You can probably get one for free…

-Pete


On Feb 11, 2012, at 1:15 PM, Nathan House wrote:

{Quote hidden}

> -

2012\02\12@154022 by Eric Kort

flavicon
face
On Sun, Feb 12, 2012 at 9:04 AM, Mark Hanchey <markspamKILLspampixeltrickery.com> wrote:
{Quote hidden}

I second the "Not what the OP asked for but still...".  With a
transformer I pulled out some old appliance, an LM317, a few diodes
and resistors, a potentiometer and a switch I made my own power supply
in an evening.  I just use my voltmeter to set the voltage I need for
any given application.  Save for the LM317 and a bit of perfboard,
everything else could easily be pulled out of some other broken piece
of household electronics.  So my total cost was around $1.50.

Oh, and for style points I housed it all in a plastic diaper wipes
box.  For the leads I used a shielded stereo RCA cord I had laying
around and put a couple alligator clips on the end (again...style
points).

Again, not what you asked for.  But more fun.  And cheaper.  I'm sure
someone else will answer your actual question =)

-Eric

2012\02\13@063537 by alan.b.pearce

face picon face
> I second the "Not what the OP asked for but still...".  With a transformer I pulled
> out some old appliance, an LM317, a few diodes and resistors, a potentiometer and a
> switch I made my own power supply in an evening.  I just use my voltmeter to set the
> voltage I need for any given application.  Save for the LM317 and a bit of
> perfboard, everything else could easily be pulled out of some other broken piece of
> household electronics.  So my total cost was around $1.50.

In the longer term I would add one of those digital voltmeter boards (can you still get them) that used a 40 pin LSI and 4 digit 7 segment display, so you have a permanent voltmeter on the output.

For extra brownie points make a project out of a PIC that has a 12 bit ADC, and a keypad for setting the voltage, and maybe also current limit, and be able to display both current and voltage.


-- Scanned by iCritical.

2012\02\13@104337 by John Ferrell

face
flavicon
face
How about a recommendation on the current limiting function?

In the longer term I would add one of those digital voltmeter boards (can you still get them) that used a 40 pin LSI and 4 digit 7 segment display, so you have a permanent voltmeter on the output. For extra brownie points make a project out of a PIC that has a 12 bit ADC, and a keypad for setting the voltage, and maybe also current limit, and be able to display both current and voltage.

-- John Ferrell W8CCW
Be thankful we're not getting all the
government we're paying for. - Will Rogers

2012\02\13@111007 by 'Shawn

flavicon
face

> If you are willing to do a bit of hacking and are willing to settle for some
fixed outputs, then you can get a ATX
> power supply from a computer and hack in some banana jacks for the 3.3, 5, and
12V outputs. You can probably
> get one for free…
>
> -Pete
>

There is a blurb on a website about doing
this,www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-Power-Supply.
Also, since you are on the PIClist, using a PIC and a LCD display (ebay, 3$ with
shipping) you could have a nice display too :-). Several have built them as PIC
projects (documented on Youtube as PIC projects but not sure how they did them
except one fella used a DAC, which I have never used.)I wondered if you used a
Pic to control the adjust current on a LM317 (as mentioned earlier, 1 Amp)  or
LM350 (3 Amp), could you build a nice inexpensive PS? I guess it is kind of
turning into a project.

I am new to PIC's but figure they are so versatile, they could add a lot of
capabilities and control to a PS.

Shawn


 
> On Feb 11, 2012, at 1:15 PM, Nathan House wrote:
>
> > I'm burning through batteries like nobody's business and think it's
> > high time I purchased a power supply. I know I can make my own board
> > with voltage regulators for common voltages like 3.3, 5, 12, etc, but
> > I think I'd rather have something that's adjustable and can source a
> > lot of current in case I ever need it. I've been looking at power



2012\02\13@112315 by Chris Roper

picon face
If you are interested in controlling a linear regulator with a PIC I
suggest you watch this:

http://www.youtube.com/watch?feature=player_embedded&v=YaRDbw38x7Q

it is part 4  of an excellent series of video tutorials, I
highly recommend them all, but that is the one most relevant to this thread..

Here is the main link if anyone is keen to watch the rest:

http://www.eevblog.com/episodes/

Cheers
Chris


On 13 February 2012 16:35, 'Shawn <.....sdonohueKILLspamspam.....tbaytel.net> wrote:

{Quote hidden}

>

2012\02\13@112344 by Michael Rigby-Jones

flavicon
face


> -----Original Message-----
> From: EraseMEpiclist-bouncesspam_OUTspamTakeThisOuTmit.edu [piclist-bouncesspamspam_OUTmit.edu] On Behalf
> Of John Ferrell
> Sent: 13 February 2012 15:44
> To: Microcontroller discussion list - Public.
> Subject: Re: [EE] Need a cheap power supply
>
> How about a recommendation on the current limiting function?
>
> In the longer term I would add one of those digital voltmeter boards
> (can you still get them) that used a 40 pin LSI and 4 digit 7 segment
> display, so you have a permanent voltmeter on the output. For extra
> brownie points make a project out of a PIC that has a 12 bit ADC, and a
> keypad for setting the voltage, and maybe also current limit, and be
> able to display both current and voltage.

FWIW I have a PSU right here on my desk that has keypad entry of voltage and current, and I really don't get on with it.  It's very easy to accidentally press the wrong button, or not notice that the decimal point was missed and suddenly have 10x more voltage than you actually wanted.  To be fair you can set an over voltage protection level to ensure this doesn't happen, but you have to make sure you type this in correctly as well.

The PSU underneath in (Keithly 2400 Sourcemeter) is slightly better - you select each digit in the voltage and increment or decrement it, but it's still not a pleasant interface.  If I was making my own digitally controlled interface, it would use a rotary encoder, and it would have pre-settable upper and lower limits so you could crank the voltage up or down with impunity whilst watching a scope display etc.

Whilst on the subject, an LM317T circuit is certainly better than nothing, but an adjustable current limit is a 'must have' for any remotely serious development work.  Applying 5v 1.5 Amps to your new circuit will probably show you that you put an IC in backwards, but it's unlikely to work after you correct it...  A bench PSU with adjustable current limit is also useful for battery charging duties.

Regards

Mike

=======================================================================
This e-mail is intended for the person it is addressed to only. The
information contained in it may be confidential and/or protected by
law. If you are not the intended recipient of this message, you must
not make any use of this information, or copy or show it to any
person. Please contact us immediately to tell us that you have
received this e-mail, and return the original to us. Any use,
forwarding, printing or copying of this message is strictly prohibited.
No part of this message can be considered a request for goods or
services.
=======================================================================

2012\02\13@114712 by alan.b.pearce

face picon face
{Quote hidden}

Yes, I have a 2400, and have to admit its front panel interface is not terribly ergonomic. It would probably be preferable to remote control it.

The only power supplies I have with keypad interface are Thurlby Thandar 35V 10A units which are rather overkill for the OP - but they are nice units. In addition to the keypad interface they have a rotary knob to fine adjust once the voltage is set, and then once current is being drawn there is a smaller display showing the VA being drawn from the supply.

This is a later version of the ones I have http://www.tti-test.com/products-tti/psu/tsxp-series.htm



-- Scanned by iCritical.

2012\02\13@142626 by Dwayne Reid

flavicon
face
At 02:15 PM 2/11/2012, Nathan House wrote:
>I'm burning through batteries like nobody's business and think it's
>high time I purchased a power supply.
>http://www.ebay.com/itm/Precision-Lab-PS305D-Variable-30V-5A-DC-Power-Supply-/120716204084?pt=LH_DefaultDomain_0&hash=item1c1b3f1834

I've had very good luck with similar power supplies.  I have single, dual and triple supplies - most are made in Asia and all have been excellent.

The better of these use linear regulators and have relays that select the appropriate tap on the power transformer so as to limit power dissipation in the pass elements.  You will relays clicking as you change the voltage knob from min to max on these units - that noise is a GOOD thing to hear.

Although the price on the unit that you linked to is reasonable, I've seen better prices on similar units.  It might take an hour or more searching to find these deals (eBay is great) but you can save significant cash if you spend the time.  Be sure, though, to include shipping in each seller's total cost before doing your comparisons.

You CAN make your own power supply - its a great early project that will last you for years.  I built several small power supplies while I was a teenager (or even before) - the best units were based on LM723 regulator chips with external pass devices.  You can build a 1A or 2A supply easily but the heatsink starts to get HUGE as you exceed 2A.  And - its hard to find power transformers that have multiple secondary taps at the proper ratios to do any good for auto-switching into your linear regulator.  Most transformers have an available center-tap but you really need 4 taps or so to keep the heat sink small.

dwayne

-- Dwayne Reid   <@spam@dwaynerKILLspamspamplanet.eon.net>
Trinity Electronics Systems Ltd    Edmonton, AB, CANADA
(780) 489-3199 voice          (780) 487-6397 fax
http://www.trinity-electronics.com
Custom Electronics Design and Manufacturing

2012\02\13@151521 by Mark Hanchey

flavicon
face
On 2/13/2012 2:26 PM, Dwayne Reid wrote:
> You CAN make your own power supply - its a great early project that
> will last you for years. I built several small power supplies while I
> was a teenager (or even before) - the best units were based on LM723
> regulator chips with external pass devices. You can build a 1A or 2A
> supply easily but the heatsink starts to get HUGE as you exceed 2A.
> And - its hard to find power transformers that have multiple secondary
> taps at the proper ratios to do any good for auto-switching into your
> linear regulator. Most transformers have an available center-tap but
> you really need 4 taps or so to keep the heat sink small. dwayne
One easy solution is to move to a switching circuit for the conversion from high voltages to lower ones. The LM2576 series of parts is probably the easiest switching device I ever used.  Add a diode and an inductor and it handles up to 3A.
Mark

2012\02\13@154612 by KPL

picon face

I just recalled I have seen a pic-controlled psu here:
http://mondo-technology.com/Bench.html

(yes, the same guy who made legendary superprobe)

On Mon, Feb 13, 2012 at 18:23, Chris Roper <KILLspamcaroperKILLspamspamgmail.com> wrote:
{Quote hidden}

>> -

2012\02\22@205620 by Nathan House

picon face
Update..

I ended up either making a good decision or a bad decision. I was
watching a power supply (BK Precision 9123A, 0-30V, 0-5A) that looked
really nice on ebay when I first asked my question, but didn't think I
would end up buying it as it looked like quite an expensive one. I
bought it. Unfortunately I went way over budget and paid $191.27 with
$26.83 shipping, so $218.10 total (yikes!). I guess it's worth it if
it's something I'll use for a long time, though. Here a a few
pictures:

www.roboticsguy.com/uploads/gallery/album_17/gallery_1_17_134741.jpg
www.roboticsguy.com/uploads/gallery/album_17/gallery_1_17_78118.jpg
http://www.roboticsguy.com/uploads/gallery/album_17/gallery_1_17_25254.jpg

It seems to work alright, but I don't have the right cables for it so
I haven't connected a load yet.

What do you think?

-Nate

On Mon, Feb 13, 2012 at 3:46 PM, KPL <spamBeGonekpl.listesspamBeGonespamgmail.com> wrote:
{Quote hidden}

>>> --

2012\02\22@212424 by peter green

flavicon
face
Nathan House wrote:
> Update..
>
> I ended up either making a good decision or a bad decision. I was
> watching a power supply (BK Precision 9123A, 0-30V, 0-5A) that looked
> really nice on ebay when I first asked my question, but didn't think I
> would end up buying it as it looked like quite an expensive one. I
> bought it. Unfortunately I went way over budget and paid $191.27 with
> $26.83 shipping, so $218.10 total (yikes!). I guess it's worth it if
> it's something I'll use for a long time, though. Here a a few
> pictures:
>
> www.roboticsguy.com/uploads/gallery/album_17/gallery_1_17_134741.jpg
> www.roboticsguy.com/uploads/gallery/album_17/gallery_1_17_78118.jpg
> http://www.roboticsguy.com/uploads/gallery/album_17/gallery_1_17_25254.jpg
>
> It seems to work alright, but I don't have the right cables for it so
> I haven't connected a load yet.
>
> What do you think?
There are two things I don't like about it.
1: It's only single output, IMO a bench supply should be dual output as many analog circuits need both positive and negative supplies
2: It doesn't have binding posts. I want to be able to stick bare wires on my PSU directly without having to worry about fitting connectors first.

For a general lab power supply i'd much rather have dual outputs and binding posts than programability and super accurate output voltages

2012\02\22@213313 by Marcel Duchamp

picon face
On 2/22/2012 5:56 PM, Nathan House wrote:
{Quote hidden}

Score!  That's an $800 supply!

At 30V and 5Amps, it will be a work bench work horse.  Plus it has a knob.  Digital programmable supplies are fine - for lab fixtures, production work, etc. but with no knob, they suck for engineering work. Yours has the best of both.

Yes, you could build your own and learn a lot.  You could learn that there is more to building a nice supply than you think.  Having a nice supply and getting on with fun tinkering work is a lot more fun.

In my book there are three pieces of test equipment you want done right:
a) power supply
b) DVM
c) oscilloscope

You should have lots of fun with your new supply

2012\02\22@220057 by Eric Kort

flavicon
face
On Wed, Feb 22, 2012 at 9:24 PM, peter green <plugwashEraseMEspam.....p10link.net> wrote:
{Quote hidden}

I'm a little confused (not hard to do).  Yes, it says single output,
but it has +, -, and ground connectors.  So if it is set, say, to 25V
as shown in one of the figures, it would also supply +12.5V and -12.5V
relative to the ground connector, right?

Pretty!

-Eri

2012\02\22@221457 by Kerry Wentworth

flavicon
face
Eric Kort wrote:
{Quote hidden}

Kerry

2012\02\22@221632 by Marcel Duchamp

picon face
On 2/22/2012 6:24 PM, peter green wrote:
>> What do you think?
> There are two things I don't like about it.
> 1: It's only single output, IMO a bench supply should be dual output as
> many analog circuits need both positive and negative supplies
> 2: It doesn't have binding posts. I want to be able to stick bare wires
> on my PSU directly without having to worry about fitting connectors first..
>
> For a general lab power supply i'd much rather have dual outputs and
> binding posts than programability and super accurate output voltages.

I would have agreed with Peter - about a 1/4 century ago.  All the analog circuitry I worked on before that time did indeed have bipolar supplies. But all things shall pass and bipolar supplies more or less have.  I certainly love having bipolar supplies for op-amp circuits but, well, I have not used them in at least 25 years. Out in my garage is an analog computer but it has lost lots of its relevance.

As far as the output connectors go, there are plenty of options to remedy those 'safety' connectors

2012\02\22@223536 by IVP

face picon face
>> many analog circuits need both positive and negative supplies

I have a dual output supply but rarely use the negative. It is handy
for op-amps and audio/power amplifiers, but the vast majority of
the time it's on a 'digital' voltage - 3V3, 5V or a battery simulation
voltage. If really necessary it's not difficult to make a negative supply,
albeit probably not tracking, with an SMPS I

2012\02\22@230315 by V G

picon face
On Mon, Feb 13, 2012 at 6:35 AM, <RemoveMEalan.b.pearceEraseMEspamEraseMEstfc.ac.uk> wrote:

> For extra brownie points make a project out of a PIC that has a 12 bit
> ADC, and a keypad for setting the voltage, and maybe also current limit,
> and be able to display both current and voltage.
>

Sounds like my next project. I should be able to get the PIC to drive a
switched mode power supply with its PWM, but I don't know how to make a
switched mode power supply and how to calculate the PWM values and stuff to
create voltage/current/whatever.

Any hints

2012\02\22@232953 by David Duffy (AVD)

flavicon
face
On 23/02/2012 2:03 PM, V G wrote:
> On Mon, Feb 13, 2012 at 6:35 AM,<RemoveMEalan.b.pearcespam_OUTspamKILLspamstfc.ac.uk>  wrote:
>
>> For extra brownie points make a project out of a PIC that has a 12 bit
>> ADC, and a keypad for setting the voltage, and maybe also current limit,
>> and be able to display both current and voltage.
>>
> Sounds like my next project. I should be able to get the PIC to drive a
> switched mode power supply with its PWM, but I don't know how to make a
> switched mode power supply and how to calculate the PWM values and stuff to
> create voltage/current/whatever.
>
> Any hints?


Check out Dave Jones' PSU project:
www.eevblog.com/2011/11/28/eevblog-221-lab-power-supply-design-part-1/
David...

-- ___________________________________________
David Duffy        Audio Visual Devices P/L
Unit 8, 10 Hook St, Capalaba 4157 Australia
Ph: +61 7 38235717      Fax: +61 7 38234717
Our Web Site: http://www.audiovisualdevices.com.au
___________________________________________

2012\02\23@002607 by V G

picon face
On Wed, Feb 22, 2012 at 11:29 PM, David Duffy (AVD) <
RemoveMEdavidTakeThisOuTspamspamaudiovisualdevices.com.au> wrote:

>  Check out Dave Jones' PSU project:
>
> www.eevblog.com/2011/11/28/eevblog-221-lab-power-supply-design-part-1/
> David...
>
>
That was an interesting watch, but I don't want to use a linear regulator.
I want to have active feedback in a self-designed switched mode power
supply using a PIC, or an opamp if the PIC isn't fast enough

2012\02\23@003446 by David Duffy (AVD)

flavicon
face
On 23/02/2012 3:25 PM, V G wrote:
> On Wed, Feb 22, 2012 at 11:29 PM, David Duffy (AVD)<
> EraseMEdavidspamspamspamBeGoneaudiovisualdevices.com.au>  wrote:
>
>>   Check out Dave Jones' PSU project:
>>
>> www.eevblog.com/2011/11/28/eevblog-221-lab-power-supply-design-part-1/
>> David...
>>
>>
> That was an interesting watch, but I don't want to use a linear regulator..
> I want to have active feedback in a self-designed switched mode power
> supply using a PIC, or an opamp if the PIC isn't fast enough.

No problem.  It was more to get ideas in general. :-)
David...

-- ___________________________________________
David Duffy        Audio Visual Devices P/L
Unit 8, 10 Hook St, Capalaba 4157 Australia
Ph: +61 7 38235717      Fax: +61 7 38234717
Our Web Site: http://www.audiovisualdevices.com.au
___________________________________________

2012\02\23@071259 by Eric Kort

flavicon
face
On Wed, Feb 22, 2012 at 11:03 PM, V G <RemoveMEx.solarwind.xKILLspamspamgmail.com> wrote:
> On Mon, Feb 13, 2012 at 6:35 AM, <alan.b.pearceSTOPspamspamspam_OUTstfc.ac.uk> wrote:
>
>> For extra brownie points make a project out of a PIC that has a 12 bit
>> ADC, and a keypad for setting the voltage, and maybe also current limit,
>> and be able to display both current and voltage.
>>
>
> Sounds like my next project. I should be able to get the PIC to drive a
> switched mode power supply with its PWM, but I don't know how to make a
> switched mode power supply and how to calculate the PWM values and stuff to
> create voltage/current/whatever.
>
> Any hints?

I think the previously mentioned EEVblog series on power supplies
should do the trick, of which episode 4 addresses PWM:

http://www.eevblog.com/2011/12/07/eevblog-225-lab-power-supply-design-part-4-pwm-control/

-Eri

2012\02\23@092858 by Paul Hutchinson

picon face
{Quote hidden}

IMHO that's an excellent choice for a power supply, we've been using one of
its ancestors (#1635) since 1988 and it has been flawlwss. B&K prodcuts may
cost more than other brands but the long reliable life more than makes up
for the price.

Paul Hutch

>
> -Nate
>

2012\02\23@095528 by jim

flavicon
face


It looks great, and the programmability would be handy in some cases.
The only negative thing I can say about it is that it's only a single
ended output.  Positive and Negative outputs would be a better choice.
However, if you don't work with Opamps or Analog circuitry very much,
this unit will work well.

Regards,

Jim

> ---{Original Message removed}

2012\02\23@095722 by jim

flavicon
face

RONG, THE gREEN gROUNFD LUG IS earth GROUND.

Regards,

Jim

{Quote hidden}

> -

2012\02\23@095856 by jim

flavicon
face

lOOK AT THE mICROCHIP WEBSITE AND LOOK IN THE aPNOTE SECTION.  tHERE
ARE SEVERAL NOTES ON smps USING pic'S.

Regards,

Jim

> ---{Original Message removed}

More... (looser matching)
- Last day of these posts
- In 2012 , 2013 only
- Today
- New search...