Hi All

I'm sure that the Peak unit (and others) discussed recently are very
nice, but could anyone point me to an open source ESR tester, or at
least the principles required to build one.

For one, I want to save money but at the same time, I really like to
make my own kit where practical.

Yes, I could go Google, but sometimes it's nice to get real
recommendations from real people ;-)

Cheers

Matthew Smith
South Australia

Matthew Smith wrote:
Hi All

I'm sure that the Peak unit (and others) discussed recently are very
nice, but could anyone point me to an open source ESR tester, or at
least the principles required to build one.

For one, I want to save money but at the same time, I really like to
make my own kit where practical.

Yes, I could go Google, but sometimes it's nice to get real
recommendations from real people ;-)

Cheers

Matthew Smith
South Australia

Use a time domain reflectometer.

Just hook a scope to the cap and hit it with the fastest rise
step you can muster. Keep it below half a volt amplitude so you
don't turn on junctions. Stated another way, build your own TDR.

If you know the source voltage and source impedance, you can easily
calculate the ESR from the size of the initial step. You can also
calculate ESL from the overshoot and capacitance from the time constant.

Using this method, you know exactly what you're dealing with. You're
not relying on some readout number that may or may not reflect what's
really going on.

mike

--
Return address is VALID but some sites block emails
with links. Delete this sig when replying.
..
Wanted, PCMCIA SCSI Card for HP m820 CDRW.
FS 500MHz Tek DSOscilloscope TDS540 Make Offer
Wanted, 12.1" LCD for Gateway Solo 5300. Samsung LT121SU-121
Wanted 12" LCD for Compaq Armada 7770MT.
Bunch of stuff For Sale and Wanted at the link below.
MAKE THE OBVIOUS CHANGES TO THE LINK
htremovethistp://www.geocities.com/SiliconValley/Monitor/4710/

For one, I want to save money but at the same time, I really like to
make my own kit where practical.

Yes, I could go Google, but sometimes it's nice to get real
recommendations from real people ;-)

Matthew Smith
South Australia

order it he
http://www.nuovaelettronica.it/it/po...&w.kit_id=4899

about 25 $ plus shipping.
Absolutely performing!!!

Matthew Smith wrote:
Hi All

I'm sure that the Peak unit (and others) discussed recently are very
nice, but could anyone point me to an open source ESR tester, or at
least the principles required to build one.

For one, I want to save money but at the same time, I really like to
make my own kit where practical.

Yes, I could go Google, but sometimes it's nice to get real
recommendations from real people ;-)

Cheers

Matthew Smith
South Australia
Here's about as cheap as you can get, provided you have a 'scope. I use
mine quite a bit and have had pretty good success. Look he

http://octopus.freeyellow.com/99.html

On Sat, 09 Apr 2005 16:58:10 +0930, Matthew Smith
put finger to keyboard and composed:

I'm sure that the Peak unit (and others) discussed recently are very
nice, but could anyone point me to an open source ESR tester, or at
least the principles required to build one.

For one, I want to save money but at the same time, I really like to
make my own kit where practical.

My local DSE store has Bob Parker's Mark I kit for ~AU$40. Only two
left last time I checked.

Otherwise try these:
http://www.siliconchip.com.au/cms/A_103805/article.html
http://www.siliconchip.com.au/cms/A_103243/article.html


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

Get the Bob Parker kit from Dick Smith or direct from Bob and you wont
regret getting this great instrument. most of us Aussie techs use it.
"Franc Zabkar" wrote in message
...
On Sat, 09 Apr 2005 16:58:10 +0930, Matthew Smith
put finger to keyboard and composed:

I'm sure that the Peak unit (and others) discussed recently are very
nice, but could anyone point me to an open source ESR tester, or at
least the principles required to build one.

For one, I want to save money but at the same time, I really like to
make my own kit where practical.

My local DSE store has Bob Parker's Mark I kit for ~AU$40. Only two
left last time I checked.

Otherwise try these:
http://www.siliconchip.com.au/cms/A_103805/article.html
http://www.siliconchip.com.au/cms/A_103243/article.html


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

"Matthew Smith" wrote in message
...
Hi All

I'm sure that the Peak unit (and others) discussed recently are very
nice, but could anyone point me to an open source ESR tester, or at
least the principles required to build one.

For one, I want to save money but at the same time, I really like to
make my own kit where practical.

In "PopTronics" (USA) July 2001, pages 25-28 there is a build it yourself
design that uses a few common parts and has full protection. It claims to
test in circuit from 1 uF on up.

You may find copies at larger libraries under "Popular Electronics",
"PopTronics" was a later name.

--
N

Max Harding vk3jin wrote:
Get the Bob Parker kit from Dick Smith or direct from Bob and you wont
regret getting this great instrument. most of us Aussie techs use it.

What do you actually use it for?
Seems that every time I want to know ESR it's in a power supply or on
a motherboard with a dozen hooked in parallel thru ground/power planes.
I've had zero success finding bad caps.

Out of circut, yes, but if you're gonna go to the hassle and board risk
of removing the cap, might as well replace it. Half the time, have to
pull the leads out and remove 'em one at a time from the ground plane.
Holes are just too tiny to suck out the solder while the lead is in there.

Over the decades, I've tried 35pS TDR to try to isolate caps.
Tried spectrum analyzer with tracking generator to sweep power/ground
planes while shorting caps to look for change.

It's rare that there's only one cap, and with those, you can just look
for ripple while it's operating.

So what's the magic method for finding high ESR caps in-circuit in a
typical situation of parallel caps?
mike
--
Return address is VALID but some sites block emails
with links. Delete this sig when replying.
..
Wanted, PCMCIA SCSI Card for HP m820 CDRW.
FS 500MHz Tek DSOscilloscope TDS540 Make Offer
Wanted, 12.1" LCD for Gateway Solo 5300. Samsung LT121SU-121
Wanted 12" LCD for Compaq Armada 7770MT.
Bunch of stuff For Sale and Wanted at the link below.
MAKE THE OBVIOUS CHANGES TO THE LINK
htremovethistp://www.geocities.com/SiliconValley/Monitor/4710/

On Sat, 09 Apr 2005 16:58:10 +0930, Matthew Smith
wrote:

Hi All

I'm sure that the Peak unit (and others) discussed recently are very
nice, but could anyone point me to an open source ESR tester, or at
least the principles required to build one.

For one, I want to save money but at the same time, I really like to
make my own kit where practical.

Yes, I could go Google, but sometimes it's nice to get real
recommendations from real people ;-)

Cheers

Matthew Smith
South Australia


I used a shunt ohmmeter cct. with the meter signal rectified
and driven by a twin-T osc at 33KHz driving an LM386. Experiment with
series resistor to get the meter range, and calibrate with resistors.
Mine reads 0 to 75 ohms at about two-thirds deflection.

I built the Elektor Electronics ESR tester and it's great:

http://www.elektor-electronics.co.uk...th=9&art=50741



Matthew Smith wrote in message ...
Hi All

I'm sure that the Peak unit (and others) discussed recently are very
nice, but could anyone point me to an open source ESR tester, or at
least the principles required to build one.

For one, I want to save money but at the same time, I really like to
make my own kit where practical.

Yes, I could go Google, but sometimes it's nice to get real
recommendations from real people ;-)

Cheers

Matthew Smith
South Australia