Need advice or first-hand experience with LC100-A and T86

[Stealth]

Howdy,

a friend of mine who is going to be winding pickups along with me found the following two items on evilBay:

LCR, RCL INDUCTANCE, CAPACITANCE, RESISTANCE METER T86 | eBay
LC100-A High precision Inductance / Capacitance meter | eBay

Does anyone have any experience with either of the two LCR meters and would you recommend getting either of them? I seem to remember the first one being offered locally, but it didn't have good reviews. The other one appears to have been made as a DIY project, which I don't necessarily consider to be an evil - knowing the meters and tools you guys here make I'd be more likely to trust that.

Any first-hand reviewers?

[StarryNight]

you need to know the test frequency of the meter. The first link doesn't mention the frequency. the second looks like it doesn't measure within the audio range. The Extech 380193 seems to be the standard model everyone uses. If you can find a meter with similar specs then it should work.

[Stealth]

Thanks for the tip. There's no data on the first item, and the second is obviously out of range. I'll have to look elsewhere, or wait till I'm confident enough in my winding abilities to warrant the need for an Extech. Gotta break a few eggs first and all that.

[Joe Gwinn]

The thing to be aware of is that many handheld LCR meters are by design unable to accurately measure the inductance of guitar pickups because pickups have a high DC (and AC) resistance compared to their inductance. Some meter circuits can handle this, and some cannot. The ones that cannot will give wildly wrong answers on pickups.

The first place to look is the instrument's spec sheet and users guide, where the technical specifications are stated. The instrument should be able to measure coils with inductance in the ~2-20 Henry range having a D around 0.5 or 1.0 (or, equivalently, 1/D=Q= 2 or 1 or so), at 1 KHz. If there is no statement about D or Q, the meter is unlikely to work with pickups.

If you search the Forum, you will find multiple postings on how to test a meter for suitability using an audio transformer or Wah inductor in series with a potentiometer.

[salvarsan]

Quick note on the Extech 380193

When measuring inductance, the Extech reports 'D' as damping factor = 1/Q.
Better to have it report L and Q since you tend to get more significant figures with Q, particularly from a guitar pickup.

When measuring capacitance, D is the dissipation factor and the reported Q tends to be meaningless or out of range.