Commonly used relays include Power Relays, electromagnetic relays, solid state relays, time relays, temperature relays, etc. Relays are devices that use the effects of current to close or open circuits for active maintenance and active control. In most cases, the relay is an electromagnet whose armature can close or break one or several contact points. When there is a current passage in the winding of the electromagnet, the armature is attracted by the electromagnet, thus changing the condition of the contact. Now let us briefly introduce the detection method of the relay:
1. Detect the relay coil: adjust the multimeter to "R*100" or R*1K". The two pens are connected to the two pins of the relay. The multimeter indication should match the coil resistance of the relay. If the resistance is significantly biased Small, it clarifies that the coil is short-circuited, if the resistance is zero, clarify the short circuit between the two coil pins; if the resistance is infinite, clarify that the coil has been broken, the above three conditions clarify that the relay is now damaged.
2. Detecting the relay contact: connect the relay coil to the regular working voltage, and use the multimeter "R*1K" block to detect the on/off condition of the contact. When the operating voltage is not applied, the normally open contact should be unreachable, and the normally closed contact should be turned on. When adding the operating voltage, the relay should be heard. At this moment, the normally open point should be turned on, the normally closed point should be blocked, and the switching contact should be switched accordingly, otherwise the relay is damaged, for multiple sets of contact relays. If some contacts are damaged, the other contacts can still be used normally.