How do you measure voltage in a curcuit?
Yes you need to use a voltmeter or a multimeter with a voltage scale. Voltage is always measured with respect to 2 points in a circuit. Most common DC circuits use a common output of the power supply for one of the points and call this ground (abbreviated GND). The black terminal of your meter is usually attached to this point while the red is used to measure voltages in the rest of the circuit with respect to this ground point.
