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