When measuring resistance with a multimeter, what should a technician do first?

Before measuring resistance with a multimeter, it is essential to disconnect the circuit from the control equipment. This step ensures that the multimeter can accurately measure the resistance without interference from power sources. When the circuit is live, current flows through the components, and this can lead to misleading readings, potential damage to the multimeter, or safety hazards for the technician.

By disconnecting the circuit, the technician isolates the component being tested, allowing for a safe and precise measurement of resistance. This practice not only protects the integrity of the multimeter but also ensures compliance with proper safety protocols in electronic maintenance and troubleshooting.