RF or even switching transistors like the 2N2222 can be used in this circuit. The capacitors are ceramic and the frequency is determined by the crystal.
This circuit is from the National Semiconductor's Linear Application Handbook of 1994. The same...
This circuit detects when there was a power cut, triggering the indicator circuit around it. The...
Found in a 1977 amateur radio publication, this circuit uses contemporary power transistors. No...