This circuit was taken from an old American documentation. It can be built with modern op amps. The power supply does not have to be symmetrical.
With the coded activation of the relays, it is possible to control which of the 16 outputs...
The integrated circuit used in this application is not very common. Transistors and resistors...
This simple circuit makes use of neon lamps to indicate the voltage of a power grid. The lamps are...