- on Miscellaneous Electronics
- Published in issue 1/2001 on page 0
Operation and design
In many circuits the switching action is performed by a relay, which in turn activates an external load. This part of the circuit is rarely covered in the accompanying text, but there is more than meets the eye if you want to design a relay driver properly.We should really look at the relay driver as a type of interface. After all, it forms the link between the control circuitry or PC and the outside world. The relay is used by the control circuitry to switch external appliances, lamps, pumps, sirens, etc on and off.Because they’re used so often, the relay driver is as common as the integrated voltage regulator, an LED driver or a power-up network. The description usually skims over the operation of these basic circuits. We feel we should look at the relay driver circuit in more detail.