Hello. Need assistance from someone id'ing a disk capacitor in an old crossover from 1980's. I spent about an hour last night researching on how to decypher the code on ceramic disk capacitors but never found one like mine. Attached is a photo. Could anyone assist me in ID'ing the specs for this capacitor, value, voltage, tolerance, etc..
Thank you.
Thank you.
Attachments
Yes, it is not a capacitor, it is a speaker driver protection device (polyswitch/Positec).
It goes high resistance on overload then returns to its normal low resistance of a fraction of an ohm after the overload condition has been removed.
You should measure its resistance because, after a prolonged period of overload, a Positec can fail to return to its normal low resistance value on removal of signal, and can stay high resistance.
If high resistance, bypass it.
P.S. If you don't continually play your speakers at excessive volume, the device may be omitted from the crossover circuit.
It goes high resistance on overload then returns to its normal low resistance of a fraction of an ohm after the overload condition has been removed.
You should measure its resistance because, after a prolonged period of overload, a Positec can fail to return to its normal low resistance value on removal of signal, and can stay high resistance.
If high resistance, bypass it.
P.S. If you don't continually play your speakers at excessive volume, the device may be omitted from the crossover circuit.
Nasty things for high quality audio, because the resistance changes with signal input. I.e. non-linear.
True, but it's a safety device.
Blown tweeters sound even worse 😊
That said, it does not distort waveforms, its time constant is way longer than any Audio frequency passing through it.
RE: Yes, it is not a capacitor, it is a speaker driver protection device (polyswitch/Positec).
If I decide to keep the polyswitch in the XO, what value would I order based on the PU3N marking?
If I decide to keep the polyswitch in the XO, what value would I order based on the PU3N marking?
Have you measured the resistance of the Positec?
According to your other thread, it is protecting the tweeter, so expect a resistance in the order of 0.4 ohm (remember to subtract the resistance of your meter leads from the total meter reading.)
If that is the case, you can confidently reuse it.
P.S. The marking on the PTC resistor doesn't help much as different manufacturers use different codings.
According to your other thread, it is protecting the tweeter, so expect a resistance in the order of 0.4 ohm (remember to subtract the resistance of your meter leads from the total meter reading.)
If that is the case, you can confidently reuse it.
P.S. The marking on the PTC resistor doesn't help much as different manufacturers use different codings.