Capacitor Help

"gecono"

** Be more careful where you read things. ** Yeah - 0.1 uF polystyrenes are a bit rare. ** A polyester type will be fine.

........ Phil

You'll be lucky to find a polystyrene cap in a value as large as 0.1uF ! It would cost nearly a king's ransom anyway ! Also, polystyrene caps are extremely rare these days. I even heard that production of the film has ceased, so in due course they're likely to 'die out' totally.

Where did you read this idea that a polystyrene would be good for this ? I suspect you've misunderstood the issues.

I have myself used polystyrene caps in the past for filters because (and this is the real reason) they were normally close tolerance (2% or 1%) and were even available from some suppliers in E24 values. For an accurate filter, you need accurate close tolerance values and polystyrene caps were the only ones readily available with those characteristics.

In your non-critical application, I'm totally sure a boring 5 cent polyester / mylar film type will be just fine.

Gragam

Thanks for the information. I guess I should have done a better job researching. I was getting my information from the following link:

I was referring to the applications column for the polystyrene where it states for "tuned circuits, timing and filters". Seems naive on my part now.

-george

BTW - As you can probably tell I'm just starting with this fun stuff. Programmer by trade, tinkerer by night ;)

"gecono"

** The note should have included the words " high stability ..... "

The tuned circuits and filters where you see polystyrenes used are ones that use precision inductors.

...... Phil