"non-polar" capacitor?

Dale H. Cook radiotest at juno.com
Mon Aug 1 06:08:41 CDT 2016

At 04:03 AM 8/1/2016, drlegendre wrote:

>Non-polar caps are used in locations where they must pass AC.

Conventional polarized aluminum and tantalum capacitors are also used in locations where they must pass AC, such as interstage coupling capacitors and bypass capacitors, not to mention electrolytics as power supply filter capacitors. Any capacitor that could not pass AC would not be a capacitor.

There are two principal situations where non-polar electrolytics are used:

1) When there is no constant DC offset to the applied voltage - if the voltage applied to an electrolytic capacitor reverses the capacitor can be damaged. When there is no constant DC offset the second reason can come into play:

2) When a large value non-polarized electrolytic can, as previously noted, cost less than a large film, oil-filled, or other non-polar capacitor.

Some of us still deal daily with analog circuitry at work.

Dale H. Cook, Radio Contract Engineer, Roanoke/Lynchburg, VA

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