This is a combined circuit of tone generator and preamplifier. We found it in a 1975 documentation. Operational amplifiers of that time can be replaced by modern equivalents.
This alarm oscillator was found in the December 1974 issue of Radio Electronics magazine. The...
We found this small audio amplifier in the November 1999 issue of Electronics Now magazine. The...
This circuit is a continuation of the previous one, serving as a protector against overloads in...