Which technician is correct regarding the removal of power before testing a circuit with an ammeter and an ohmmeter?

When assessing the removal of power before testing a circuit with an ammeter and an ohmmeter, it is essential to understand the working principles of both measuring devices.

An ammeter measures current, and it should be connected in series with the circuit. For safety and accuracy, power must be removed from the circuit before connecting an ammeter. This ensures that the circuit is not live during the connection process, which reduces the risk of electric shock as well as avoids damage to the ammeter.

An ohmmeter, on the other hand, measures resistance by sending a small current through the component being tested. This device also requires power to be removed from the circuit before testing. If power is left on, the readings can be inaccurate as the voltage present can affect the resistance measurement, and it may also cause damage to the ohmmeter.

Therefore, both technicians are correct in asserting that power should be removed before using their respective testing devices. It is crucial to ensure that the circuit is not energized when performing both types of measurements for safety and accuracy purposes.