Before using a voltmeter, a technician should always set the range selector to what?

Setting the range selector of a voltmeter to a value higher than the expected voltage is a critical practice for several reasons. Primarily, doing so helps to prevent potential damage to the voltmeter. If the selected range is lower than the voltage being measured, it could exceed the device's maximum input capacity, resulting in a blow fuse or related damage.

By starting with a higher range, technicians can safely measure a wide array of voltages without risking equipment failure. If the initial setting is too high, the voltmeter will still work safely, and the technician can then refine the selection further downwards to obtain a more accurate reading while ensuring they remain within the safe operating limits of the device.

Inaccurate readings can also occur if the range is set too low, leading to readings that may not reflect the actual voltage present. By starting with a higher range, technicians ensure they avoid this risk, capturing the true voltage without potential overload issues.

While other choices like auto-range may seem convenient, it’s not the most reliable option in all scenarios, as some technicians might prefer to have control over the ranges according to their experience and specific needs of the situation.