This circuit was found in a 90s Wels' Think Tank. The frequency depends on C2 and R3. The handset or speaker must be at least 80-ohm. Observe the low supply voltage.
This circuit is for collectors. It is the circuit of one of the most popular transistor radios of the...
This circuit was found in the December 1991 issue of Radio Electronics magazine. The circuit is...
Found in a QST magazine from the 90s, this circuit broadcasts on different amateur radio bands...