Capacitor meter/checker

[J Rindt]

Do any of you guys use a in-circuit cap meter.?
Something like the Capacitor Wizard perhaps.......?
Just wondering if there are any "stand out" models that kind of set the standard for these devices......
Thank You

[stratele52]

I have 2 capacitor meter , one old ( like new ) Heatkit capacitor checker and on one new digital Metermaster.
Both need you should disconnect one end of the cap to check if you want accurante mesurement . In circuit mesurement  doesn't work ; too much caps inside the circuit.

[HotBluePlates]

The only useful feature of most cap meters is determining the value of an unknown cap (or one that might have aged significantly).

You don't run into a need for this often in amp work. I think the last time I actually measured caps in this manner in a guitar amp was back around 1997. I found that most coupling caps were similar to their marked value, and most electrolytics had aged to be quite a bit lower than the marked value. I could have guessed that as a rule of thumb without measurement.

Some of the old-school cap checkers allowed a measurement of value, but also tested with the presence of d.c., and also allowed a measurement of leakage current. That could be valuable, but you'd have to know how to interpret the results. A coupling cap might leak d.c., but if it's very low and the following stage's grid reference resistor is not high, you could call the cap good. A new electrolytic might leak very much more current, but still be functioning exactly as it should.

For what it's worth, you could measure leakage current with a cap connected to a d.c. supply and a sensitive voltage or current meter. If you already have these, the cap checker doesn't have much value. If you don't, the old-school cap checker is usually much cheaper than buying a d.c. supply and (yet another) good meter.

[stratele52]

+1 HotBluePlate

[jjasilli]

Ditto to Hotblue & statele52.  I have a vintage Eico 950B R-C Comparator which can measure caps at up to 500V.  But I hardly ever use it.  E.g.:  it's easy to test a signal cap for DC leakage in circuit with a volt meter.  Old electrolytics I automatically replace.