Subject: Re: easy fast rise time pulse generator?
Date: Sat, 12 Oct 2002 19:36:31 -0700
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It's not easy to make a flat top on a avalanche generator in the 10uS/division
You can meet the 2N2222 spec with just about any transistor process. You'll
a wide variation in avalanche performance among vendors and vintages of parts
the same part number. Don't get discouraged if it don't avalanche, try another
of transistor. If you can borrow access to a curve tracer, you can easily sort
thru a handfull
of misc transistors to find the avalanche characteristics you desire.
Also, be careful with the output. There's a lot of peak energy coming out of
You can build an attenuator that looks good at 1MHz, but lets the full amplitude
of the transient come right thru and blast whatever you're testing.
You're gonna still have the same problem you have with any pulse generator
You need a good calibrated scope with performance better than the generator to
set it up.
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Phil Hobbs wrote:
> RA wrote:
> > You could use an avalanche pulse generator and get 300 ~ 350 ps rise/fall
> > time with a pulse repetition of a few hundreds of kHz. You'll need only a
> > 2N2222, 3 resistors and a cap. This can be set in and running in 10 min.
> Do you have a working schematic?
> Phil Hobbs