ESR meter upgrades

[stj]

Re: ESR meter upgrades

i tried supercaps long ago when these things first came out and they where identified as a "cell" so it thought it was charging a battery!!
i dont know if that has improved since.

actually i think i have one - i'll report back.

[eccerr0r]

Re: ESR meter upgrades

I think the meter's fine, reports "no or unsupported device" with nothing plugged in, and remains in capacitor mode when the supercap is removed - but whether it detects supercaps correctly is the question... 9% loss is pretty huge, and 21mF vs 0.047F is about half, though I'd expect leakage to increase apparent capacitance instead of decrease.

Then using jumpers testing a 10000uF/16V, 4700uF/35V, and a 4400uF/50V standard capacitors and they came up pretty close to expected readings... just the supercap might be bad?

[stj]

Re: ESR meter upgrades

if you run it with nothing what does it say?
biggest problem i'v had with these units is leaky or shorted protection diodes

[eccerr0r]

Re: ESR meter upgrades

More interesting things to measure.
Tried measuring a 0.047F supercap.

It reported 21.xx mF with ~9% loss and ~8Ω ESR.

Hmm... not sure what to make of this. Bad EDLC or confused meter...

[stj]

Re: ESR meter upgrades

got bored,
made a quick build for GM328's - the real ones with a monochrome display, not the black clones of an "AY-AT".

20MHz only - because you should be too.
rotary encoder helps

[stj]

Re: ESR meter upgrades

the newer software and a faster crystal can improve that, or go all out and add this:

[eccerr0r]

Re: ESR meter upgrades

So far at least for capacitors that have wire leads, transistortester doing a good job for them IMHO, at least in one test it shows more information about the capacitor that I'd need multiple instruments to do.

transistortester just seems to be doing a not so good job with thyristors that can be plugged into it.

I'm also somewhat surprised it can test inductors...well, dismayed that microhenry inductors don't do so well but millihenry inductors read fine.

[stj]

Re: ESR meter upgrades

the mcu can push/pull 30mA, the limit is caused by the resistors.

[redwire]

Re: ESR meter upgrades

You need a high current pulse to test ESR with bigger capacitors. If a good portion of that pulse is lost in the leakage current, then the ESR reading is wrong but capacitance should be wrong as well (if it's using single-slope technique).
The Anatek Blue ESR meter has three constant-current test levels - 0.5mA, 5mA and 50mA which works well. It's only an 8usec wide pulse, and check is on the ramp up and down.

ESR meter - it might be the firmware's timing for when to apply the pulse and then sample with the A/D? Maybe the gap is not extended with the faster MCU crystals? Not sure how it measures ESR.
chinese electrolytics act more like leaky batteries, tough to figure out if the part works lol.
I think this tester needs to get out of cheap town and somebody blow the budget and add a transistor lol, so it can pump some decent test current out - into a capacitor or diode or whatever. I thought it's just 5V/680R or under 7mA but the MCU's output drop is also in the way.

[eccerr0r]

Re: ESR meter upgrades

yeah, at least it displays loss, but it's still wrong Seems like it will still try to generate a capacitance reading, as long as it doesn't leak way too fast...

[stj]

Re: ESR meter upgrades

but the full software shows the leakage too

[eccerr0r]

Re: ESR meter upgrades

At least it does OK measuring ESR

Unfortunately it does seem to get tricked by leaky capacitors. Tried making an artificial leak and the capacitance went up...

[stj]

Re: ESR meter upgrades

6mA is the test current.

[eccerr0r]

Re: ESR meter upgrades

Have to admit this is kind of disappointing that it can't detect high power thyristors and it's even frequently wrong...

Oh well.

[stj]

Re: ESR meter upgrades

i have tried a bunch of triacs and sometimes they are id'd as scr's other times as transistors.
i suspect it's down to how the triac reacts at low current.

[eccerr0r]

Re: ESR meter upgrades

Interesting, yeah kind of figured it couldn't supply much current. Still wonder why darlingtons show up real low in gain however.

It could detect thyristors, but had problems with a few to220 thyristor as well.

It detected one of my BT136's as a BJT with very high hFE, and another as (unidirectional) thyristor... Can't trust this the tester for high current devices it seems, have to go back to manual hand testing.

[stj]

Re: ESR meter upgrades

triacs dont work - they need too much current to turn on

[eccerr0r]

Re: ESR meter upgrades

hmm... playing with transistortester... found a few parts that it doesn't seem to work or maybe my parts are broken... was there any firmware history that perhaps a newer firmware would detect:

- I have one TO220 TRIAC that it thinks is dead, though I thought this TRIAC was NIB. Hmm. I have another, very low power TRIAC that it does detect.
- A unijunction transistor, it detects as two diodes.
- Darlington transistors like TIP125, beta is very low. Vbe is also lower than expected.
- A lot of other TO220 BJT return very low betas (sort of expected at high current however, but how much current is it testing?). TO92 and TO39 transistors, beta is much higher.

I had this one TO5 transistor that was really weird as it was open all around. I concluded without the transistortester that it was a E-MOSFET. So I finally gave it a go and it agreed with me that it indeed was an E-MOSFET. It seems to correctly identify N-JFET that I had as well.

Found a few bipolar capacitors that probably needs to be binned at 11Ω ESR...

Generally an interesting tool...

[stj]

Re: ESR meter upgrades

I just think there's no excuse to send 8 characters per second to the HD44780, just to save a pin/lazy code!

that would be classed as a piss-take!!

[eccerr0r]

Re: ESR meter upgrades

I just think there's no excuse to send 8 characters per second to the HD44780, just to save a pin/lazy code!