Re: noise question

On 7/15/24 16:30, john larkin wrote:

Does a negative 50-ohm resistor make as much noise as a regular 50 ohm
resistor?
 I'd sorta guess the current noise to be the same, and maybe the
open-circuit voltage noise is infinite.
 I could Spice that, at least the current noise, if Spice handles it
right. LT Spice noise analysis is kind of weird.
 

I just tried it: In LTspice the sign doesn't matter,
only the absolute value. Also, if you put a positive
resistor in series with negative one, the noise
voltages add RMS-wise, like you'd expect of independent
sources.
In real life, a negative resistor may have more or
less noise than an actual resistor, depending on the
low-noise design skills of the designer.
I think you knew that...
Jeroen Belleman