This circuit was found in a National Semiconductor manual from the 1980s. The integrated circuits used are equivalent. Note the need for a symmetrical power supply.
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...