"Fred Bartoli" r_AndThisToo
wrote in message ...
A small cap (1n or so) across the 1K feedback resistor will be welcomed too.

Is that meant to surpress any spikes when the '4051 switches (i.e,. if it
"breaks" before it "makes")?

It's kind of a clever circuit, IMO. What do the circuit design gurus think of
it?

I'm waiting to hear someone suggest you could do this with an 8 pin PIC or
AVR... 4 lines to the '4051, and another one to receive frequency commands
over, e.g., RS-232. :-)