New idea sawtooth generator (fwd)

Ric Miller rmiller at
Tue Jul 11 01:13:24 CEST 1995

From: Rick Jansen <rick at>
To: Synthesizer DIY list <synth-diy at>
Subject: New idea sawtooth generator
I just had a new idea to get rid of the discharge time in 
a sawtooth generator. Why not take TWO integrating capacitors
and switch the charging current and output for each half of 
the wave. This way one capacitor gets linearly charged while
the other can be relatively slowly discharged. It sure will 
be utterly discharged the moment the other integrator reaches
peak level. I propose to use 1% styroflex capacitors for this
purpose, which are easy to get.

Uh oh.  Now you've caught me.  :)  I can't see what the problem is
with the old sawtooth generators, that a new one is needed ....

Each integrator has its own comparator, one controlling the set,
the other controlling the reset of a flipflop. The Q and !Q of
the FF control some 4066 switches.

4066 switches?  I don't know the specs of them off hand, but these are
high voltage switches.  Why not use 4016 switches?  (The latter I know
of a 300 ohm ON impedance).
Or how about JFET transistors as the switches?

Curious ....


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