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.
The circuit presented may use any general purpose transistor. The indicator is an LED and...
The operational amplifier used in this project no longer exists, but the circuit can be adapted to...
This car battery monitor was featured in the January 1988 issue of Radio Electronics magazine. The circuit...