Peak Atlas ESR tester

[Boulevardier]

Originally Posted by high_vacuum_house

The Peak ESR tester does have a built in capacitor discharge cycle which detects non discharged capacitors, applies this cycle before testing the capacitor. I think the operating limits are as above though if the capacitor takes too long to discharge then it warns you it’s taking too long, aborts the discharge cycle and test.

Christopher Capener

Thanks Christopher. That actually sounds like pretty good protection. Peaks are quite expensive, and I'd worry about destroying one in a moment of absent mindedness. But it sounds as though you'd have to be criminally careless to damage one. Worth the expense of getting one, I think.

Mike

[CambridgeWorks]

How about fitting a sprung dpdt switch between tester and the croc clips or whatever. Normally, both poles switched into say a 47R wirewound resistor, until you press the switch to connect clips through to tester?
Cheap and simple.
Rob

[Boulevardier]

Originally Posted by robinshack

How about fitting a sprung dpdt switch between tester and the croc clips or whatever. Normally, both poles switched into say a 47R wirewound resistor, until you press the switch to connect clips through to tester?
Cheap and simple.
Rob

Yes, using a biased input switch for the unprotected Chinese tester had also occurred to me, though you'd have to short all three connection leads to the tester to be safe (since you can use any two of the three connectors, and leave it to the tester to sort out which is which). But for a large capacitor discharge might take longer than it took you to operate the biased switch, so the Peaks' "programmed" approach would be safer.

Apart from all this, do the Peaks have other advantages over the cheapies? And they certainly are cheap by comparison! I know that their wider functions aren't accurate for germanium junctions, but perhaps the Peaks are also silicon-only (talking about the models that include semiconductor testing).

Mike

[chriswood1900]

My Peak old DCA55 and new DCA75 correctly identify Germanium and Silicon parts when testing.

[CambridgeWorks]

Boulevardier wrote: "But for a large capacitor discharge might take longer than it took you to operate the biased switch, so the Peaks' "programmed" approach would be safer. "
What I meant was biased so as to put the resistor continuously across the "probe" contacts. Operate the switch (removing load) to test with the esr meter.
3 Pole switches are available.
Rob

[poppydog]

How high a voltage (charged capacitor) will these testers safely discharge?

poppydog

[mhennessy]

See post #18

[Boulevardier]

Originally Posted by robinshack

Boulevardier wrote: "But for a large capacitor discharge might take longer than it took you to operate the biased switch, so the Peaks' "programmed" approach would be safer. "
What I meant was biased so as to put the resistor continuously across the "probe" contacts. Operate the switch (removing load) to test with the esr meter.
3 Pole switches are available.
Rob

Yes, I meant that too, but my point was that you can't be sure that the capacitor has fully discharged by the time you operate the switch and remove the bleed resistor (assuming a large capacitor). The Peak's approach of monitoring the discharge and only connecting when/if complete (assuming I've understood it correctly) seems safer .

Mike

[poppydog]

Originally Posted by mhennessy

See post #18

Sorry,

poppydog

[David G4EBT]

The only thing I'd say about an ESR meter, is that it's a 'one trick pony' as compared to a multi tester. I've got an older DAC50 and a DCA 55, which was an impulse buy when Maplin briefly had an offer - about £20.00 I think - I wouldn't have paid much more. I don't want to knock Peak equipment, which enjoys a high reputation, is British made, and to all accounts has excellent backup support and helpful staff. That said, neither the DAC50 or DAC55 compare favourably with Chinese multi testers when testing FETs. I've mentioned this before, but it's relevant to this thread.

First pic below is of a JFET on the (quite old) DAC50 which claims to test FETs but never has. It thinks what it sees is a diode.

Second pic is the JFET on the DAC55. If identifies it correctly as a P Channel JFET.

Third pic is to identify the JFET connections, but can't identify the Drain and Source.

Fourth pic is a Chinese Multi tester - no difficulty in identifying that it's a JFET and the pinouts.

Fifth pic is a second Chinese Multi-tester. As with the first, it correctly give the pinouts, and the data is consistent with the other Chinese tester.

(I've got a third Chinese tester which came as a kit as a gift from a forum chum and that too, gives consistent results).

I don't need yet another tester, but if I did, It would be the ubiquitous MK-328, which is an LCR, transistor and and ESR meter. It has some limitations in that it won't test caps below 30pF or low inductances, but then neither would a Peak ESR meter or transistor tester. The full spec of the MK-328 can be found at one of the many ebay sites that sell them, but I've shown an Amazon link, where at £21.95 post free it costs a few pounds more than from China but you get it in a few days rather than a few weeks.

https://www.amazon.co.uk/ROKOO-Trans.../dp/B07429JHJ5

Not trying to start a 'beauty parade' of ESR meters, and really, the original question about the Peak Atlas ESR meter has been well answered, but I thought some comments about the limitations I've found with the DAC55A when it comes to testing FETs were worth a mention.

Hope that's of interest.

[Boulevardier]

David - thanks, you give (as usual!) a very interesting and thorough breakdown. The Chinese (mainly ATmega328 based) testers really do seem to run rings around any single Peak instrument - I even came across one offering IR testing). And most can be had for under £10! But it seems that all of them lack protection against connection of charged capacitors.

At that price it would be well worth fettling one to try and provide some protection against charged capacitors (let's face it, even the most careful of us is probably going to slip up on that eventually). I've been trying to think of an effective way of doing that. A biased "start" switch as suggested by Robinshack might be a start, though large capacitors might need a carefully considered delay before operating the start switch.

Still thinking...

Mike

[factory]

I'm very happy with the second hand Peak ESR60 I bought last year, I did consider the ESR70 but didn't need the buzzer or the extended ESR range it provides, if the capacitor ESR is higher than the ESR60 can measure I figured it's probably junk anyway.

David

[David G4EBT]

Originally Posted by Boulevardier

David - thanks, you give (as usual!) a very interesting and thorough breakdown. The Chinese (mainly ATmega328 based) testers really do seem to run rings around any single Peak instrument - I even came across one offering IR testing). And most can be had for under £10! But it seems that all of them lack protection against connection of charged capacitors.

At that price it would be well worth fettling one to try and provide some protection against charged capacitors (let's face it, even the most careful of us is probably going to slip up on that eventually). I've been trying to think of an effective way of doing that. A biased "start" switch as suggested by Robinshack might be a start, though large capacitors might need a carefully considered delay before operating the start switch.

Still thinking...

Mike

A decade ago or more ago, before Peak and before Chinese Multi-testers, it was the norm for many to build a homebrew ESR meter using an analogue meter movement. Most designs had some sort of protection built in. The one that I built back in 2010 based on a design by a Canadian radio amateur had a protection circuit which included a 0.47uF 400V capacitor and a few other bits. Time moves on, and apart from the enjoyment of homebrew - for those that do enjoy it - it makes little sense to build an analogue meter using a 50uA meter movement, which alone will cost around £10.00, when a Chinese Multi-test can be had for as little as that.

That said, a homebrew ESR meter can be simply and accurately calibrated, and will perform just as well as a commercial digital one.

The fact that the thread ran for 4 years, had 106 posts and has had 71,000 views is as much an indication of the interest of measuring ESR, and opinions as to whether to test caps in situ or not, and 'at what ESR does a good cap become a bad cap?', as it has to do with the original project. Forum member 'Top Cap' designed a stripboard layout for those that didn't have PCB facilities. (Post 29 of the thread):

https://www.vintage-radio.net/forum/...esting+el+caps

The thread became so involved the Joe, 'Pillenwerfer', kindly drew the strands together and created a PDF, which is attached. (I'm referred to as 'Yorkie' in that document as that's what I'm known as elsewhere). There's some information about ESR meters in general which might be of interest, and the ESR table by Bob Parker referred to in the text is attached below.

I hope it's sufficiently relevant to this thread to be of interest.