I have an old tube radio. There is a ceramic cap with:"RMC / 0.1 / 1400V / Z5U " written from top to bottom, respectively. Now, this cap has broken at it's base and can't be resoldered and so must be replaced. I have another ceramic disk cap, almost the same radius (across the flat aspect) with: " RMC / 0.5 / 20% +- / Z5U " written on it in the same fashion.
I'm wondering what the voltage rating of this possible replacement cap is and whether or not it would make a suitable replacement for the whacked one.
I've been looking ALL OVER the Net for info on ceramics and their voltage ratings when not shown on the cap. I found nothing so any help would be appreciated. I read something that I find highly suspicious so I won't poison the mental pool here with that particular suggestion but I am quite interested in what the EE community has to say.
Best Answer
My hunch is that the part is 100nF, and your replacement is 500nF.
I wouldn't risk using a cap without a voltage rating indication on it. Also, you're better off replacing that Z5U dielectric with one that's more temperature stable, like NP0.
I'd source a 100nF, 2kV NP0 capacitor as a replacement.