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.
This circuit was found in the July 1990 Radio Electronics magazine. It is based on the 3-digit...
This circuit can be used on sound mixers to obtain effects. We found the circuit in a 1997...
This oscillator uses a ceramic resonator to determine the frequency. This kind of element is found...