Buying a ESR meter for In Circuit testing... [EVB Meter purchased.]

[Shock]

Heavy-duty protection. To provide greater protection against connection to charged electrolytics, some kit builders have connected an inverse-parallel  pair of  1N5404 (or  similar) high-power diodes between the test lead sockets. So if you’re the kind who’s likely to connect the meter to the 120?F input filter capacitor of a 240V-powered switching power supply without checking that it’s been properly discharged,   this modification is for you.

Reportedly, this protects the meter quite well, although it can result in the probe tips being blown off by large charged capacitors. The resulting surge current can also damage the charged capacitor and the power diodes themselves. However, without the diodes, the resulting >600A current spike destroys the microcontroller (IC2) and damages C6.

So they are put across the test leads and if any voltage higher than the forward or reverse of the diode it creates a short through the leads instead of through the rest of the instrument.

[SeanB]

Correct, and works well. Adds a bit of capacitance to the unit and a little leakage, but when compared to the expected results it will only make a small difference with any capacitor under 1uF and with an ESR over 1k, so basically does not make any difference to your usual sub 1 ohm capacitor over 100uF. I used 1n400x diodes as they were to hand when i built mine years ago, and it probably will survive albeit the diodes will fail most likely short circuit.

[Mp3]

I bought the Peak ESR meter with the EEVblog discount!  It is a great device and works well.

Woah, what is this! How much was it with discount? 

[Mp3]

If you don't have a bench LCR/ESR then the DE 5000 ~$100 is the is best bang for buck handheld LCR/ESR meter. If you want to go cheap as possible then the Chinese $20 LCR/ESR. They don't have any input protection or discharging.

The Peak ESR testers are limited to discharging at around 50V, so not designed for mains voltage protection. It does show capacitance as well as ESR on screen, aside from that it's a small subset of the above testers functionality.

The Bob Parker based designs I would say are the most robust if you buy a model with (or add your own) input protection. This would be my personal choice for an off the shelf tester. You are going to find it harder to kill if you make some mistakes.

My current method for testing:
Discharge the caps through a resistor shorting lead
Check the DC voltage for safety
Check the DC resistance for low resistance shorts
Check the ESR

Parallel capacitance and resistance will be included in the ESR measurement, you may need to remove components regardless to get a clean measurement.

My worries about the 5000 are if a battery gets put in backwards and it goes poof. I always check stuff but sometimes i get distracted and it is possible. It is not a huge worry but i was a little put off by its complexity, whereas the other ones are pretty dead simple "stick the leads on and get a number".

[nanofrog]

I bought the Peak ESR meter with the EEVblog discount!  It is a great device and works well.

Woah, what is this! How much was it with discount? 

FWIW, they ran a sweet deal here on the forum (limited time offer aspect = was absolutely clear).
That said, send an email and see what they have to say.

[Mp3]

I bought the Peak ESR meter with the EEVblog discount!  It is a great device and works well.

Woah, what is this! How much was it with discount? 

FWIW, they ran a sweet deal here on the forum (limited time offer aspect = was absolutely clear).
That said, send an email and see what they have to say.

Unfortunately i have not been on this site longer than a couple of weeks, and only in the Beginners forum, i will try to contact them and see what they have to say.

[andreimaxim]

I bought the Peak ESR meter with the EEVblog discount!  It is a great device and works well.

Woah, what is this! How much was it with discount? 

FWIW, they ran a sweet deal here on the forum (limited time offer aspect = was absolutely clear).
That said, send an email and see what they have to say.

Unfortunately i have not been on this site longer than a couple of weeks, and only in the Beginners forum, i will try to contact them and see what they have to say.

The discount still worked on the site 12 hours ago. However, I found that the discounted price + shipping outside of UK was roughly just as expensive as buying from a local dealer.

[Shock]

I found this Bob Parker ESR meter kit listed at DELSOUND in Brisbane (Aust) http://delsound.com.au/hardware/kits/red-k2574

Just putting it out there. At A$71 it is surprisingly cheaper than Altronics selling their own (same) kit at A$90. Whether they have stock is another matter.

I put a pair of beefy diodes in for good measure too.

Did it have the Altronics logo on it?