Buying a ESR meter for In Circuit testing... [EVB  Meter purchased.] - Page 1
Forum section: electronics / beginners

author: Mp3
author_rank: Frequent Contributor
timestamp: February 24, 2018, 01:14:17 am
content: 2-27-2018 I went for the Portugal made EVB Meter, because it was about $20 less than the Blue ESR meter pre assembled and seemed more sturdy. I almost went for the cheap Mega powered china ESR meter but reliability will be most important for me checking lots of caps frequently.Hello everyone,I bought a cheap meter on amazon just to find it was a LSR meter only, so i sent it back. I'm looking at ESR meters and deciding between the AnaTekBlue ESR Meter($95 + shipping USD) or theEVB ESR Meter(~$78 USD with shipping)seems like the EVB comes with test leads and alligator clips, whereas i would have to get those separate with theBlue ESR meter.Anyone have any other suggestions, my only requirement is under $100 USD assembled and ready to go. I have projects waiting on me to get this to complete them, so i don't want to save a few bucks by building the kit...PS If i am testing in circuit, if the power cable is disconnected and i flip the power switch to "on" and leave it for about 30 seconds, would that discharge the capacitors safely to test them with the meter?

author: BradC
author_rank: Super Contributor
timestamp: February 24, 2018, 01:16:50 am
content: Any of the Bob Parker designs are good for in-circuit. The Anatek is one of those (or was when I last checked).

author: Mp3
author_rank: Frequent Contributor
timestamp: February 24, 2018, 01:17:47 am
content: Quote from: BradC on February 24, 2018, 01:16:50 amBoth the anatek and EVB are! I'm having trouble finding out what differentiates them though.

author: Macbeth
author_rank: Super Contributor
timestamp: February 24, 2018, 01:44:48 am
content: I would go for a DER EE DE-5000, but beware you will have to choose the correct mode and a suitable frequency to probe your capacitor with and also it has no input protection so make sure the DUT it completely discharged before connecting it to your circuit.

author: Electro Detective
author_rank: Super Contributor
timestamp: February 24, 2018, 02:12:58 am
content: The Peak Atlas ESR70 is a great no brainer ESR meterI couldn't get a Bob Parker pre-assembled unit in a hurry so I took a gamble with this = good choice, works great

author: Mp3
author_rank: Frequent Contributor
timestamp: February 24, 2018, 02:28:20 am
content: Quote from: Electro Detective on February 24, 2018, 02:12:58 amGeez, it's the most expensive of all but that auto discharge feature looks like it could come in handy for testing in circuit. The price difference if I zap a Bob Parker or DER is a whole new unitQuote from: Macbeth on February 24, 2018, 01:44:48 amI will look into the DE-5000! I was just trying to find out if it can discharge, but it looks like only the Peak does that.

author: Electro Detective
author_rank: Super Contributor
timestamp: February 24, 2018, 02:36:08 am
content: Yeah mate, it's not cheap and you should still stay on top of making sure ALL caps are discharged, or are at low voltage levels the Peak can handleand watch out for battery leakage in any of these brands, or you'll be spending twice

author: Macbeth
author_rank: Super Contributor
timestamp: February 24, 2018, 02:37:22 am
content: Quote from: Mp3 on February 24, 2018, 02:28:20 amThe Peak may discharge but only up to some level. If you are probing a mains PSU how do you know those caps aren't holding 330 VDC which will destroy the Peak or any other meter?It seems to me it's easy enough to just discharge every circuit before probing with any gear.

author: nanofrog
author_rank: Super Contributor
timestamp: February 24, 2018, 02:43:38 am
content: Quote from: Mp3 on February 24, 2018, 02:28:20 amUnfortunately it doesn't.So you'll have to bleed caps prior to testing. Ye olde short the leads with a screwdriver.IIRC, another member added a discharge circuit so that may be worth a search.

author: Electro Detective
author_rank: Super Contributor
timestamp: February 24, 2018, 03:51:15 am
content: Or cover the circuit in cooking foil for a quick no frills global discharge..no wait, don't do it!let me confirm first that this 'urban' method actually works and without caveats

author: Mp3
author_rank: Frequent Contributor
timestamp: February 24, 2018, 04:53:31 am
content: Quote from: nanofrog on February 24, 2018, 02:43:38 amWow, i never thought about a discharge circuit mod. I have seen the DE-5000 can be ordered from Japan for under $80 shipped if not shipped express. I will look for used ones as well before going for a Bob P. design. Thank you allEdit: Just searched de-5000 mods, de-5000 discharge etc but not finding anything about a discharge circuit mod? Are you talking about the unpopulated space on the pcb for input protection which i saw mentioned?

author: floobydust
author_rank: Super Contributor
timestamp: February 24, 2018, 05:24:07 am
content: Quote from: Mp3 on February 24, 2018, 02:28:20 am

author: BradC
author_rank: Super Contributor
timestamp: February 24, 2018, 05:30:20 am
content: I put a couple of back to back clamp diodes inside my Bob Parker unit just in case. I haven't tested them yet in anger but I'm pretty sure the test leads will die before the diodes. The only issue with that is it means I can't use the meter to do impedance measurements on batteries, but I didn't build it for that anyway.

author: Mp3
author_rank: Frequent Contributor
timestamp: February 24, 2018, 05:59:09 am
content: Hey, i didn't realize the Blue meter is protected against charged up caps! That's a nice featureQuote from: BradC on February 24, 2018, 05:30:20 amI don't care at all if its useless for measuring batteries. I will never be using it for that. I have a lot of in circuit caps to test and would rather spend a little more than spend time discharging caps soldered to a PCB! What kind of diodes did you use for this? When you say back to back, are they attached like decoupling caps or am i way off base?Edit: Looks like the cheaper EVB comes with diodes for protection installed. But do I want to spend the extra on the Peak which can discharge anything?

author: BradC
author_rank: Super Contributor
timestamp: February 24, 2018, 06:59:46 am
content: 1N5404 as documented here :http://bobparker.net.au/esr_meter/esrhints.htmBob used to have a great history page on what led him to develop the meter, but since he's revised his site I can no longer find it. Wish I'd archived it as it had some great background on the how and why.

author: Jwillis
author_rank: Super Contributor
timestamp: February 24, 2018, 07:29:33 am
content: I have a Mastech MS5308 LCR tester.It's also an ESR tester that works very well.It may seem expensive but it has a lot of features in one package.Check it out.

author: cowasaki
author_rank: Frequent Contributor
timestamp: February 24, 2018, 08:46:30 am
content: I bought the Peak ESR meter with the EEVblog discount! It is a great device and works well.

author: Shock
author_rank: Super Contributor
timestamp: February 24, 2018, 10:13:16 am
content: 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 leadCheck the DC voltage for safetyCheck the DC resistance for low resistance shortsCheck the ESRParallel capacitance and resistance will be included in the ESR measurement, you may need to remove components regardless to get a clean measurement.

author: nanofrog
author_rank: Super Contributor
timestamp: February 24, 2018, 03:09:14 pm
content: Quote from: Mp3 on February 24, 2018, 05:59:09 amNo. But it's just a resistor, so very easy to add.You could also add the input protection, but be aware it would affect the accuracy a bit.

author: Macbeth
author_rank: Super Contributor
timestamp: February 24, 2018, 09:47:58 pm
content: Quote from: Mp3 on February 24, 2018, 01:14:17 amThis wasn't answered, but absolutely not! Certainly not with a physical switch on the primary side, or a soft-switch powered by a low volt standby circuit on the secondary.I have to say the absolute worst ever electrical shock I had in my life was a new-fangled SMPS in a Philips TV chassis back in the early 1990's. The set had presented as totally dead. Unplugged over lunch break. Half an hour later those clearly excellent electrolytic capacitors discharged right through my thumb and left venom bites in the skin and a "tunnel" through my flesh. The pain and lasting damage was far worse than regular 240 VAC or even 30kV final anode CRT shocks. (It's ok, the damage cleared a few months later)I wouldn't trust any meter to discharge SMPS caps ever. I would use a crowbar (screwdriver) if a resistor wasn't to hand.

author: bitseeker
author_rank: Super Contributor
timestamp: February 24, 2018, 10:00:06 pm
content: When testing electrolytic caps, be sure to do so soon after discharging. They can recover a fair amount of voltage (depending on how high their voltage was prior to discharge) over time.

author: Electro Detective
author_rank: Super Contributor
timestamp: February 25, 2018, 01:50:52 am
content: Quote from: bitseeker on February 24, 2018, 10:00:06 pmOh yeahgreat heads up, sometimes they kick back to jolt life,either reform/recover by themselves or perhaps borrow electrons from elsewhere whilst operator discharges and desolders component legs to isolate and test suspect capacitorsBe on top of it ALWAYS, otherwise you'll out pocket for a new ESR meter,and maybe more cash blown if you haven't got eyewear on during an 'up close and personal' nasty metal on metal cap sparkI double check the high voltage suckers are flat with an analogue multimeter set to the highest voltage range 750>1000v,if there's serious life I drain them with a resistor again or keep the resistor on there till I'm ready to work on it

author: floobydust
author_rank: Super Contributor
timestamp: February 25, 2018, 03:50:31 am
content: Quote from: BradC on February 24, 2018, 06:59:46 amI know of Bob's Parker's original article, from Silicon Chip Magazine March/April 2004 published in Dick Smith Electronics K7214 assembly manual, he goes into detail about it.The schematic here shows the protection diodes, only 1N4004 and after the input cap, so I would still expect some damage if connected to a SMPS cap with 100V's of charge on it.

author: BradC
author_rank: Super Contributor
timestamp: February 25, 2018, 04:01:20 am
content: Quote from: floobydust on February 25, 2018, 03:50:31 amWhich is why I put the extra protection 1N5404 diodes on.

author: cowasaki
author_rank: Frequent Contributor
timestamp: February 25, 2018, 09:48:15 am
content: Quote from: BradC on February 25, 2018, 04:01:20 amI'm just following the circuit, did you just replace the 4004s with 5404s ?

author: Shock
author_rank: Super Contributor
timestamp: February 25, 2018, 10:15:22 am
content: QuoteSo 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.

author: SeanB
author_rank: Super Contributor
timestamp: February 25, 2018, 03:26:56 pm
content: 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.

author: Mp3
author_rank: Frequent Contributor
timestamp: February 26, 2018, 02:07:42 am
content: Quote from: cowasaki on February 24, 2018, 08:46:30 amWoah, what is this! How much was it with discount?

author: Mp3
author_rank: Frequent Contributor
timestamp: February 26, 2018, 02:11:27 am
content: Quote from: Shock on February 24, 2018, 10:13:16 amMy 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".

author: nanofrog
author_rank: Super Contributor
timestamp: February 26, 2018, 03:20:29 am
content: Quote from: Mp3 on February 26, 2018, 02:07:42 amFWIW, 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.

author: Mp3
author_rank: Frequent Contributor
timestamp: February 26, 2018, 03:05:18 pm
content: Quote from: nanofrog on February 26, 2018, 03:20:29 amUnfortunately 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.

author: andreimaxim
author_rank: Newbie
timestamp: March 31, 2018, 05:00:15 am
content: Quote from: Mp3 on February 26, 2018, 03:05:18 pmThe 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.

author: Shock
author_rank: Super Contributor
timestamp: April 01, 2018, 05:42:30 am
content: Quote from: wilfred on March 31, 2018, 05:45:50 amDid it have the Altronics logo on it?