Found in American documentation from the 90's, this circuit can be implemented with modern equivalent components. Observe the symmetrical power supply.
This interesting 80's EDN circuit divides the input pulse frequency by a number given by n...
Adafruit Raspberry Pi Perma Proto PCB Kits Adafruit kits are available from Mouser Electronics...
This circuit is from the Motorola Linear Databook of 1990. The coils must be according to the...