We found this circuit in the July 1990 issue of Radio Electronics magazine. The frequencies are given by capacitors C2 and C3, which can be changed.
Found in a 1968 EEE, this circuit accepts frequencies from 1 to 1000 Hz and control voltages from 0.1 to...
This circuit has appeared several times on this site in different applications. This is from 1997...
This setting appears other times in this section from other sources. This is from an 80's American...