On Sat, 11 Jun 2005 10:36:54 -0400, "Tam/WB2TT"
wrote:

snip

Yes. DC by definition is zero frequency.

Um, no. DC is Direct Current, i.e., current that flows in one
direction. For example, the output from a rectifier is DC but it
certainly isn't "zero frequency."

The output of a rectifier contains both AC and DC. You put a filter on it to
get close to pure DC.

A rectified AC waveform contains DC and AC components but if the
current isn't changing direction, it isn't alternating current. And,
if it isn't AC, it's DC.