Dr. G,
You are correct, but many circuits have used the 1N4000 series diodes as
varactors with acceptable results. Any diode is a varactor (even transistor
junctions), but those called varactors are just optimized for and
measured/spec'ed as variable caps. If the cap value works in the circuit
and losses/noise/whatever-else aren't a problem, then no problem. I chalk
it up to: Some of us don't have the luxury of either well stocked basements
or pocket books, or perhaps the willingness to run out to the local parts
store (if you have one) and pick something out just to throw some neat
little thingy together.

Don't (some) zeners generate noise???...or is that only near the breakdown
reigion?

73, Steve, K.9/D;C'I


"Dr. Grok" wrote in message
...
Maybe I'm confusing this with something else but I always thought 1N4007's
were 1000 V PIV, 1 A rectifiers.

I believe "any" diode has varactor characteristics to some extent but if
you
need a varactor you'd be better off using one designed as a varactor.

Dr. G.



In article , JE
wrote:
The common 1N4007 seem to work for HF but what is the max. frequency they
can be used as varactors?

And how about zener diodes?

JE