David:
[snip]
"David Robbins" wrote in message
...
"Peter O. Brackett" wrote in message
.net...
Slick:
What about a negative inductance for a load? A negative capacitance?
And
don't tell me those are not passive!
a negative inductance is a capacitance, and a negative capacitance is an
inductance! and yes, they are both passive!
[snip]
You are only half correct David.
They are both passive, but a negative inductance certainly is NOT a
capacitor.
And a negative capacitor certainly is NOT an inductor.
Compare the expressions below to convince yourself of the truth of this
assertion.
The inductive reactance for a positive inductor is:
X = j*w*L
of a negative inductor
X = -j*w*L
of a positive capacitor
X = 1/j*w*C = -j/w*C
of a negative capacitor
X = 1/-j*w*C = j/w*C
The magnitude of the reactance of a negative inductor goes up with frequency
while the magnitude of a capacitor goes down with frequency, etc...
I have synthesized filters with both negative inductors and negative
capacitors, they are theoretically passive and they do work.
--
Peter K1PO
Indialantic By-the-Sea, FL
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