LCR meter 4070 modification

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#1
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OK. So I rolled the dice on getting a cheap-o LCR meter. It's a model 4070 that can be found on eBay and other places. It's a neat little meter, but the ranges for inductance go from 20H down to 20mH. 20H. Really? When was the last time you worked with a 20H inductor. A lot of the stuff I'm doing now use inductors from 1uH (TI TPS63020, 2.4 MHz) to a few mHs.

So... 2 questions.
1 - Is there a decent LCR/RLC meter out there that can measure down to the uH range that won't break the bank.

2 - How does an LCR meter work? I could maybe change some component values to change the range from 20H - 20mH to 20mH - 20uH.

I figured I'd ask here first.

EDIT: The test frequency is 100Hz. If I could change the test frequency, to 1000Hz or 10,000Hz would that make a measured inductor appear larger or smaller? Could I get a 1 micro-Henry inductor to appear as though it were a 1 milli-Henry inductor? Thus lowering the overall range?

Jim M., Rank amateur AVR guy.

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XL = 2PIfL where:
XL = reactance in ohms ()
f = frequency in hertz (Hz)
L = inductance in henrys (H)

http://sites.google.com/site/vk3...
for a nice one-chip (PIC) LC meter, that works fine for uH - mH ranges (I built a couple)

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Xantor wrote:
XL = 2PIfL where:
XL = reactance in ohms ()
f = frequency in hertz (Hz)
L = inductance in henrys (H)

http://sites.google.com/site/vk3...
for a nice one-chip (PIC) LC meter, that works fine for uH - mH ranges (I built a couple)

Nice link to the PIC project.
So to keep reactance the same, a smaller inductor would require a higher frequency. I'll see what I can come up with. I'd rather just mod the existing meter than build my own.

Jim M., Rank amateur AVR guy.

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Jimmy,

Our fellow 'Freak "Plons" (Nard Awater) has a very nice design called "Elmcie" http://www.aplomb.nl/TechStuff/E...

Worth a read if nothing else ... but also worth building.

Cheers,

Ross

Ross McKenzie ValuSoft Melbourne Australia

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20H inductors are out there... The secondary coil on a transformer in a disposable camera flash circuit is typically a few henries.

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Not bad, jayjay. Thanks.

Jim M., Rank amateur AVR guy.

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Hi,

I also have the peak one that JayJay1974 has; I really like it.

Thanks,

Alan

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I have an Extech 380193. Dave (EEVBlog) made a review.

Felipe Maimon

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Thanks, guys. All good stuff. I'm going to start saving my pennies for a decent LCR.

Jim M., Rank amateur AVR guy.

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Keithley 3322 LCZ when needed

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Keithley 3322 LCZ when needed

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I have a Beckman LM22A portable LCR meter. 3.5 digit with the lowest full scale inductance being 200 uH, highest is 200 H.

Tom Pappano
Tulsa, Oklahoma

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tpappano wrote:
I have a Beckman LM22A portable LCR meter. 3.5 digit with the lowest full scale inductance being 200 uH, highest is 200 H.

Thanks. Another pretty reasonable LCR.

Jim M., Rank amateur AVR guy.