Products > Test Equipment
Getting an old-school impedance bridge, worth the hassle?
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Vincent:
(Maybe this belongs more to the Beginner section?   :-// )

I'm in the process of buying some of the basic test equipment that I still don't have and while I can pretty quickly determine whether or not I need a particular piece ("If you can't articulate why you need something, then you probably don't need it"), I'm a bit on the fence when it comes to impedance measuring instruments. I already sorta know how to figure some things out without such equipment, say track bad electrolytics. And it seems to be a better approach to test the coils/caps at their actual working frequency anyway. But I still wonder how useful an LCR meter/bridge is from a general perspective. Or is it in fact such a specialized tool that the average hobby electronics lab is no worse off without one?

Now my budget isn't that severely limited but I certainly wouldn't mind using the older manual instrument if it means saving a few $$$. I drive stick everyday, so doing the stuff manually isn't a problem.  8)

In the case it deserves a spot on the bench, any idea as to which model would be the best choice, again for sorta general purpose? I like the Leader LCR-740's compactness and 40kHz external oscillator capability. Gen-Rad models on the other hand are known for their excellent build quality (and stability it seems?). ESI ones don't seem all that bad either. Then there are a number of less common makes and models. There's even a Philips PM6301 on eBay right now which I'm tempted to buy, even if just as an expensive toy to play with LOL.
wn1fju:
LCR meters are not typically required in a home lab situation, but once you acquire one, you will say to yourself, "how did I ever live without one of these?"  They are particularly useful, for example, in identifying (unmarked) components from your junkbox. 

I have had experience with a lot of these: ESI 296, Genrad 1658, Genrad 1685, HP 4260A, HP 4261A, HP 4262A, HP 4265SA, HP 4271A, HP 4274A, HP 4332A and Sencore LC53.  Many of these are automatic meters - insert component and read the display.  But often they require an auxiliary test fixture or set of Kelvin leads.  The manual ones, for example HP 4260A and HP 4265A, are a bit more difficult to use and I've found that you sort of have to know approximately what the component's value is before you start twiddling the (two) knobs.  As you have said, ESI and Genrad make good LCR meters.  So does HP.  I would recommend the HP 4274A/4275A if you want a top-notch bench LCR meter.  I'm not a big fan of Phillips, but perhaps that is because I've had some bad experiences in the past trying to fix some of their (non-LCR) test equipment.

There are also a bunch of handheld models such as the Peak LCR45 or the BK Precision 880, or even some of the newer LCR "tweezers" if you are doing SMT work. 

Search through the eevBlog forums - many people have had recommendations.
nctnico:
IMHO an LCR meter is certainly useful but I'd get a modern (digital) one if your primary target is to actually use it for measuring components. And no, the 4274A / 4275A are not top-notch bench LCR meters. Been there, done that; it is old crap from the 80's. Technology has improved since then. GW Instek makes nice LCR meters for a reasonable price compared to Keysight.
precaud:
I'll split the difference between wn1fju and nctnico. The 4274A is not cr@p but is quite large for what it does. For bench use it would be nice if it had more freqs available, but for the high-speed sorting in an automated system that it was designed for, it is good enough. The 4275A is in a different class; covering 10kHz to 10MHz, it's a more specialized instrument. I don't use it a lot, but when you need to look at Z in that freq range, it is spot-on.

For a good, inexpensive first lcr meter, take a look at the XJW01:
https://www.aliexpress.com/item/3256801259913642.html
A friend talked me into trying one and I've been quite pleasantly surprised. I have several HP and Wayne Kerr meters and this one is accurate, warms up quickly, and is so small and handy. It also accepts the same fixtures as the HP. I'm using it a lot more than I thought, like wn1fju said, for testing components in the junkbox, verifying parts retrieved from scrapped pcbs, or quick matching/sorting while assembling. FWIW, I bought mine from the vendor in the link.
wn1fju:
I really like my HP 4274A.  The specs are generally fine for home use and seeing as I paid less than one-tenth the price of a new more modern LCR meter for it, it's good enough for me.  True, it is a relic from the 1980's and is large and bulky, but at least one has a chance of repairing the unit unlike the modern stuff.  I don't consider it "old crap from the 1980's," but that's just my personal opinion.

I only offered it as a potential solution to the original poster since it appeared to me he was interested in older models and perhaps real old ones like the manual impedance bridges.  The latter category I would, however, consider to be "old crap" unless you are talking about some of the specialized, extremely expensive bridges (Genrad, ESI, etc.) that were made decades ago and are metrology-grade.



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