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 1969 General Electric manual. The SCR may be the TIC106. Similar circuits...
This circuit is an improvement of the previous one, with the use of two transistors produces a...
This circuit was found in documentation from Analog Devices. The circuit is based on an AD795 and...