ESR Meter confusion

maysdairy · 2018-11-06T07:09:53+00:00

One of my digital multimeters has a capacitor test built into it. But I dont believe that tests the ESR. I've recently read many articles and watched videos about testing the ESR of caps. I wanted to buy an inexpensive ESR tester and went to ebay. I am just a hobbyist on a low fixed income so I cant pay a lot. Anyhow, that is where I got real confused. Several say ESR, while others are just cap testers. Looking at the pictures on the ebay pages, they all look alike. So, whaT is really different between them? I sure cant tell. Links to low cost models on ebay that would suit my needs appreciated. (I DO NOT use Amazon).

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krw 7 years ago

Can't remember the last time I saw a toumbstoned SMT part from a production, or even prototype production line. Probably at my last job - a small company trying to build on the cheap (RoHS with a three stage oven). I thought toumbstoning was a thing of the distant past.

We had that problem, too, but haven't seen it since I left there. I found it easier to just reheat all connections in the suspect area.

I use them to verify that the correct part was put on the board. Once in a while our CM screws up the SMT program. Backwards SOT23-6s seem to be their big problem.

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Phil Hobbs 7 years ago

We sometimes see dry joints in quick-turn boards, especially our last batch from Screaming Circuits--they must have used a specially-thin stencil, because there are no solder fillets at all. We probably had

15% of the boards with at least one dry joint. No bueno.

Cheers

Phil Hobbs

Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com

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John Larkin 7 years ago

The min and max are on the data sheet too. If they're not, buy something else. At three cents each, may as well but good parts from authorized distributers, so you can be confident that they meet their specs.

If you want a well matched diff pair, buy an opamp. Most dual transistors these days are just two die potted together, not very close and not well thermally coupled.

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Yikes! BJTs or mosfets hard in parallel, running in linear mode, are a recipe for endless grief.

John Larkin Highland Technology, Inc lunatic fringe electronics

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John Larkin 7 years ago

They just keep getting better! I don't think I have any circuits that mind more beta. And I prefer mosfets anyhow.

I got some smart tweezers and a vacuum part pickup thing, but don't use them. I do use my AADE l/c meter a lot.

John Larkin Highland Technology, Inc lunatic fringe electronics

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Phil Hobbs 7 years ago

More beta tends to go along with lower breakdown voltage and more capacitance. So it isn't always a benefit, by a lot.

That meter is the only electronics kit I've ever built--in 2015!

Neil was already too sick to assemble them. Poor guy.

Cheers

Phil Hobbs

Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com

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John Larkin 7 years ago

I used to build Heathkits and sell them at my cost. I just liked building them. It didn't occur to me to make a profit.

He was cool, and it's a great little instrument.

John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com

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Phil Allison 7 years ago

** Not an option with repair work.

** Even with 0.47ohm, ballast resistors, Vbe matching is still needed in most cases. Equipment makers often had the BJT maker ( like Motorola or ON) do the task for them in batches - then badge the devices with a house number.

Like I said, repair and manufacture involve different mindsets.

.... Phil

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