This is a typical circuit of a PROM programmer from the 70s. It appeared in the magazine Radio Electronics in 1979. Note that the programming was done manually byte by byte using switches.
Found in the October 1992 Radio Electronics magazine, this oscillator is controlled by switch S1....
This circuit was obtained in a 1976 amateur radio manual. The circuit can be made with a 2N2222...
The component used in this circuit is not very common today as the circuit is from the 80's. It...