1.1 Relay Failures

While there is a wide range of failure modes for relays, this application note looks at the following ones:

• Open Circuit/Closed Circuit
• Brown-out

Most of these faults appear as a difference between the detected and expected voltage. In other words, if the relay coil is not being driven, but voltage is on the output, the relay has presumably failed short through some means. This can be expanded upon to include brown-out conditions on the output.