When using an ammeter/voltmeter, what range strategy is recommended to maximize resolution?

• A. Initially choose the highest range for the ammeter/voltmeter, then reduce the range for the ammeter so that the deflection is almost full scale
• B. Always use the lowest possible range
• C. Use a fixed mid-range for all measurements
• D. Switch ranges randomly during measurements

Answer: (A)

Maximizing resolution comes from having the meter deflect near full scale, because then each small movement corresponds to a smaller amount of the quantity being measured, giving you a more precise reading. The safe way to achieve this is to start with a higher range to prevent damage if the value is larger than expected, then switch to progressively lower ranges until the deflection is almost full scale. This uses the most sensitive range for the actual measurement, giving the finest possible resolution. Using the lowest range all the time risks overloading the meter or blowing the fuse, and switching randomly or sticking to a mid-range does not optimize the reading.