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.
November 2016 - Bourns RLB1112V4 series radial inductors are available for immediate supply from...
This two-door doorbell was found in a 1990s US publication. The circuit is still current as...
This very low frequency circuit was found in a 1964 Electronic Design. Transistors may be modern...