Cheap LCR meter

[sluckey]

Cute meter. Even cheaper in the USA...

https://www.amazon.com/Proster-Multimeter-Capacitance-Resistance-Inductance/dp/B071WNNYQT/ref=sr_1_3?keywords=proster%2Blcr%2Bmeter&qid=1645187044&sprefix=proster%2Blcr%2Caps%2C93&sr=8-3&th=1

[sluckey]

So I decided to buy this little meter. Just got through testing it. I had no inductors handy, so I just checked resistors and capacitors, comparing to my Fluke 87V. It matched the Fluke on all resistance checks, 1Ω up to 10M. And it surpassed the Fluke on capacitance. My Fluke doesn't do caps below about 1000pF, but this cheap Proster LCR Meter accurately goes right on down to 10pF (smallest value in my bench stock). The largest cap I had was 250µF and the Proster and Fluke were right on.

This meter is not tough, so don't drop it. And there is no prop up stand, so it has to lay flat. But the display tilts up! The case is a bit tight, but you can put everything in it and still zip it up.

Well worth the money. I'm happy. BTW, you can find several demos on youtube.

[pdf64]

No spare OT handy as an inductance test piece?

[PRR]

What is the frequency of the inductance test? (Meter a speaker and hear the pitch.) Iron-core chokes will be much smaller above 400Hz than below 200Hz. If it sings instead of growls, it's not telling the audio (or power ripple) value.

[sluckey]

I finally decided to test PRR's idea. Sure enough, I could barely hear the tone in a speaker so I looked at the meter output with a scope. The LCR meter uses a non symmetrical square wave, approx. 1200Hz for the 200µH scale and about 400Hz for all others.

The speaker really loaded the output and made the signal look terrible. These scope pics are just with the scope connected to the meter leads.

I did measure the inductance of several OT primaries, with similar results for each one. But I had no data to compare to see how accurate the measurements would be. The only inductor I have that has a value stamped on it is a 15µH. It measured at 18µH.

[PRR]

> only inductor I have that has a value stamped on it is a 15µH.

Probably not an iron core?

What does it say for a Champ/Valco/etc output transformer? 10 Henry is the expect ballpark for the bottom of the audio band, where it matters "to us". Maybe 300mH for the speaker winding.

[shooter]

the asymmetry may be to allow the electro-magnetic field to collapse before smacking it again.

[72Blazer]

Just bought one.  None of my meters will test low pf value silver micahs.  Thanks for the info!

[72Blazer]

Got it today.  Works great.  Even came with a battery.  I can finally test the pesky pFs!  Thanks Sluckey for the info.