The relay's primary appeal is its ability to do a lesser-switch's bidding but it's capable of so much more. Relays can be wired together to create very useful, simple, and utterly reliable networks.

Some relays will become warm if they remain energized for some time. The circuit shown here will actuate the relay as before but then reduce the ‘hold’ current through the relay coil current by about ...

The circuit shown in the figure uses stored energy in the multiplexer relay coil to boost the power-supply voltage from 3.3 to 5.1 V. This extra voltage enhances the amplifier's ability to produce a ...