Help identifying an old circuit component

Thread Starter

JeffM

Joined Mar 9, 2015
13
I could really use some help identifying this circuit component. Most of the other components are new original stock from the 70s and 80s and all my attempts to identify this guy have been in vain. Any help would be appreciated, including what that symbol is/means.

Thanks!
Jeff

IMG_6849b.jpg
 

#12

Joined Nov 30, 2010
18,224
I think mica capacitors. Remember, these are 40 to 50 years old. Only a couple of decades after paper caps were used (in radios) instead of poly-film.
 

Thread Starter

JeffM

Joined Mar 9, 2015
13
Nothing on the back. My fluke multimeter cap test showed OL. First time I've ever used the cap mode, so I may need to set it down from autoscale? I tested a similar blue cap from the same era and it dialed in the right capacitor value (confirmed by google search of the lettering), but this one wouldn't register.
 

#12

Joined Nov 30, 2010
18,224
10 pf is so bloody small that the leads on your meter could cause 10% error. No surprise if the meter wasn't designed for 10 pf. Do you have meter leads or just some, "jam it in here" clips?
 

Hypatia's Protege

Joined Mar 1, 2015
3,228
Actually they appear to be 100pF etched/silver-mica caps -- in my experience numerical codes (in contrast to color codes) never set the multiplier digit = 0 hence such figures represent non-coded values. thus, in this case, "100" has the same meaning as "101"...

Just my $0.02

Best regards
HP
 
Last edited:

#12

Joined Nov 30, 2010
18,224
If it was 100 pf, it would cause a proper reading on a meter that has a lower limit of 10 pf...assuming the meter isn't broken, and Fluke has a good reputation.
 
If it was 100 pf, it would cause a proper reading on a meter that has a lower limit of 10 pf...assuming the meter isn't broken, and Fluke has a good reputation.
Interesting that the instrument shows an 'over-range' indication though (leaky NOS SMs are almost unheard of)... Absent a proper LCR indicator he needs to take your advice (i.e. measurement of several paralleled devices)... :)

Best regards
HP
 

Thread Starter

JeffM

Joined Mar 9, 2015
13
I get 0.3 ohm for all 10 in parallel. I get 10.3 ohm for one single one. confirmed across a few different tests.
 

Thread Starter

JeffM

Joined Mar 9, 2015
13
I cut one open earlier and it has a white center. Any idea what that volt symbol means? I couldn't find either a resistor shaped like this or that voltage symbol in my searches.
 
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