This version of triac control is from a 1968 documentation. The circuit uses components from the era that can be replaced with modern equivalents.
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...