Learning the LCR Meter

[voodoochild]

I just bought my first LCR Meter on Ebay. It seems pretty decent for less than $50. It's a no name LCR4070. I've been winding pickups long enough now to get one in order to make them more consistent I hope. Anyway, I was taking some readings and comparing to different brands of similar designed pickups I have in the shop, Duncans, Fender, Suhr, etc and I got different readings but I don't quite understand them all.

I set the meter to 20H to read inductance and I get these readings,
(I won't disclose the actual model in case they get mad)

Duncan Strat = 6.37H
Suhr Strat = 7.19H
My Pickup = 5.91H

I set the meter to 20nf to read capacitance and I get these readings,

Duncan Strat = 8.77nf
Suhr Strat = 7.37nf
My Pickup = 7.19nf

I understand the capacitance reading (I think) but what do the inductance readings tell me? I assume these represent actual Henries but they seem kinda high. FYI the back of the box for the Custom Shop Fender 69 Strat pickups say they are 2.2 Henries and I got almost 6H on my meter. False advertising? Or does it really matter if it sounds good, just keep the numbers in range? Thanks

[Chadheckler1]

Do you know what frequency your LCR meter is testing with? Inductance and capacitance will be different when tested at different frequecies. More expensive LCR meters have multiple test frequencies... For instance the extech can measure using a test freq of 120hz and 1khz...

[Mike Sulzer]

Low Q (high loss) inductors are hard to measure. It is unlikely that a no name meter does it right.

[voodoochild]

On the 20H setting it measures at 100Hz
On the 20nf it measures at 1kHz

[voodoochild]

This is the one I got if that helps.
http://cgi.ebay.com/3-1-2-bridge-LCR...3%3A1|294%3A50

[belwar]

Originally Posted by voodoochild

On the 20H setting it measures at 100Hz
On the 20nf it measures at 1kHz

Your examining two different points on the audio scale with that current setup. 100hz is a very low frequency (bass tone), while 1khz is a more trebley note. Read up and see if you can measure both at 1khz.

With inductance you're going to see less dramatic changes with the actual windings. Inductance really starts changing when you start mucking with the metals. For example in a humbucker your inductance can change dramatically by swapping out one set of pole screws for another, or changing the keeper bar to a different alloy.

Just so you can see a different im sitting here with one of my humbuckers and the extect meter that many people here recommend... Here are the three main items at two frequencies

Inductance (Series) @ 120hz = 4.38H
Capacitance (series) @ 120hz = 384.2nf
AC Resistance @ 120hz = 7.84 Kohms

Inductance (series) @ 1khz = 4.085H
Capacitance (series) @ 1khz = 6.158 nf
AC Resistance @ 1khz = 11.367 Kohms


The DC Resistance is 7.79 . Look at the difference in the capacitance at the two measurements.. If I remember correctly, both the inductance and capacitance will continue to drop until you hit the resonance peak frequency of the pickup. Im hoping joe or one of the electrical wizards pipes up and fixes my statement as i've just started learning about this stuff and have been piecing it together myself. I look forward to being shown the errors of my ways.

b.

[StarryNight]

would this unit serve as a less expensive substitute for the Extech for reading pickups?

[voodoochild]

Originally Posted by belwar

Your examining two different points on the audio scale with that current setup. 100hz is a very low frequency (bass tone), while 1khz is a more trebley note. Read up and see if you can measure both at 1khz.

With inductance you're going to see less dramatic changes with the actual windings. Inductance really starts changing when you start mucking with the metals. For example in a humbucker your inductance can change dramatically by swapping out one set of pole screws for another, or changing the keeper bar to a different alloy.

Just so you can see a different im sitting here with one of my humbuckers and the extect meter that many people here recommend... Here are the three main items at two frequencies

Inductance (Series) @ 120hz = 4.38H
Capacitance (series) @ 120hz = 384.2nf
AC Resistance @ 120hz = 7.84 Kohms

Inductance (series) @ 1khz = 4.085H
Capacitance (series) @ 1khz = 6.158 nf
AC Resistance @ 1khz = 11.367 Kohms


The DC Resistance is 7.79 . Look at the difference in the capacitance at the two measurements.. If I remember correctly, both the inductance and capacitance will continue to drop until you hit the resonance peak frequency of the pickup. Im hoping joe or one of the electrical wizards pipes up and fixes my statement as i've just started learning about this stuff and have been piecing it together myself. I look forward to being shown the errors of my ways.

b.

Interesting. I guess in the end it doesn't really matter what frequency you are reading in as long as you are getting a reading. Using it as a point of reference to help maintain consistency is what means the most to me right now.