Automotive Service Technician Period 1 Practice Exam

Impedance in a voltmeter tells you how much the meter itself loads the circuit. A voltmeter is designed to have very high input impedance, so it draws only a tiny amount of current and barely changes the circuit’s voltage. In other words, impedance measures how much the meter will load the circuit. It isn’t about the circuit’s maximum deliverable current, nor the total resistance of the circuit, nor the voltage across the meter (that reading is the voltage you’re trying to measure, not the impedance).