How to Test if a Relay is Good or Bad?
1 Answers
Methods to test if a relay is good or bad: 1. Use the ohmmeter function of a multimeter to measure the relay's coil. The coil should show a very small resistance value; if the resistance is infinite, it indicates an open circuit in the coil, meaning the relay is damaged. 2. Measure the normally closed (NC) and normally open (NO) contacts of the relay. The resistance values should be close to zero for the NC contacts (below 1 ohm) and infinite for the NO contacts. 3. Check if the relay can be manually operated by pushing the actuation part. If it can, keep the relay in the actuated state and then measure whether the NC and NO contacts have switched states. 4. Alternatively, directly apply the operating voltage to the coil to energize the relay, and then measure whether the states of the two types of contacts have changed.