When testing a control relay, after isolating it from the circuit, what is the next step?

• A. Apply a small AC signal to the coil and observe response
• B. Measure the coil's inductance with an LCR meter
• C. Set the meter for ohms (resistance) and check the reading across the coil leads.
• D. Power the coil briefly to see if it energizes

Answer: (C)

After isolating the relay, the next step is to verify the coil’s continuity by measuring its resistance with a multimeter on the ohms setting. A healthy coil shows a finite resistance within the coil’s specified range. If the reading is infinite, the winding is open; if it’s very low, there may be a short. This check confirms the coil is intact before any power is applied, reducing the risk of damage or misreading later.

Other methods aren’t as reliable for a basic health check: applying a signal to the coil or energizing it without first confirming continuity can mask problems or cause unnecessary risk, and measuring inductance requires specialized equipment and doesn’t directly indicate coil integrity.