This circuit is from old documentation, but it can be implemented with modern transistors such as 2N2222 for bipolar and BF124 for FET. The crystal determines the operating frequency.
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...