Final answer:
To check if a motion detector is receiving power, the meter should be on the voltage setting. Incorrectly setting it to ammeter mode during this check could short circuit and damage the meter and circuit. It is important to start with the largest scale on the meter to prevent damage.
Step-by-step explanation:
To ensure that a motion detector is receiving power from the control panel or power supply, the meter should be placed on the voltage setting. This is because you want to measure the potential difference, or voltage, supplied to the motion detector. When measuring voltage, if the meter is accidentally set to ammeter mode, it could cause a short circuit because an ammeter is designed to measure current and has very low resistance. This mistake can damage the meter and potentially harm the circuit.
Using meters correctly is important when working with electrical circuits. To prevent damage to the meter and to ensure accurate measurements, it is recommended to start with the largest scale available on the meter. This habit reduces the risk of the meter being exposed to values beyond its capacity, which could lead to the meter's failure.