Micamold capacitor

Why would it be polarized? People too often think there is some special reason for polarized capacitors, when in reality I can think of no application that would require a polarized capacitor. But, in order to fit larger capacitance into reasonable size, capacitors become polarized because they are made in a way that does cause them to be polarized.

One just looks at the value, and there's no way .05uF is large enough to require an electrolytic or tantalum capacitor. Thus it can't be polarized, there's no use in using them at that small capacitance.

What was common in the old days were capacitors where one side was best put to ground. Paper capacitors for instance, since it's a roll of foil interweaved with an insulator, one side will be more prone to stray pickup, so it should be grounded, and capacitors were marked to indicate which side. They will work in either direction, just that in one way it may pick up unwanted signals.

But that won't be relevant today, since capacitors of .05uF can easily be much smaller and with other materials, and there won't be a difference which way it gets put in.

Michael

From your description it sounds like a wax paper capacitor. The band is not for electrical polarity but denotes which end is connected to the outer foil, which was often connected to ground, assuming the circuit allows, since that would then act like a 'shield'.

You should replace all the wax paper caps too, not just electrolytics, because they fall apart, as you have noticed with that one.

Btw, you can't trust that the 'brick rectangle' ones are always mica either. Micamold was notorious for making paper caps in that shape (say, around 500pF or so and up) but others did it too.

.05uF, 150V sounds right.

"Lee K. Gleason" wrote in news:4ec9ce92$0$18905$ snipped-for-privacy@usenet-news.net:

I agree. (And at 20% tolerance). And the 503 at the end of the other number might be a forerunner of the notation now used, to mean 50,000pf so 0.05µF.

Sounds like an ordinary old wax paper condenser, definitely not polarized. What's its function in the circuit? Sounds like a real home-brew mod, as if it is grounded, the band (outside foil) should have gone to ground. An ordinary .05 mike mylar cap, 150 volts or higher, is a replacement, if that value is suitable for the circuit function.

Hank

An ordinary .05 mike mylar cap, 150 volts or higher,

Thanks all, for the info. I did that, and it works a treat!.

-- Lee K. Gleason N5ZMR Control-G Consultants snipped-for-privacy@comcast.net