A bit off-beam, that. The reverse-biased B-E
junction is a fairly good noise generator, but I expect that
reverse breakdown is not included in the model.
On 2023-07-27 02:46, Andy I wrote:
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Hyu wondered why a transient simulation doesn't show any random
noise.
The reason is simple:? SPICE is noise-free in .TRAN analysis.? It
always was.? SPICE is deterministic.
You can simulate noise in SPICE by using a .NOISE analysis.
You can also "observe" noise in a .TRAN analysis in LTspice, by
adding a B-source (behavioral source) with a white() argument.?
This will add a random (but not Gaussian) noise signal to your
circuit, but you get to decide how much noise to add, so it will
not necessarily behave like the real components (resistors,
diodes, or transistors) you're trying to simulate.
? ?Bnnn Nxxx Nyyy V=2*noise(time*2e6)
will generate white-ish noise with a bandwidth of about 1 MHz and
a peak amplitude of +/- 1 volt.? But carefully note that the
simulation settings (Maximum Timestep and Plotwinsize) may affect
how accurately the simulation follows the signal generated by the
white() function.
Andy
John Woodgate