This 5.1 MHz circuit was found in a 1980s documentation. The frequency is given by the crystal and general purpose transistors can be used.
This circuit is from a 1965 Electronic Design. The transistors may be general purpose and the...
Also suitable for use as a noisy alarm, this Morse Code or telegraph practice oscillator was found...
This preamplifier is recommended by Sanyo and is based on its LA3160 integrated circuit. The...