Voltage is always referenced to something, usually a local ground. To measure a voltage, you will first connect the ‘common’ jack of the meter to the circuit common (i.e., breadboard ground). Next you will connect the meter’s ‘voltage’ jack to the point of interest. The meter will then tell you the voltage with respect to ground at this one point.
When connecting things, it’s always a good idea to use color coding to help keep track of which lead is connected to what. Use a black banana plug lead to connect the ‘common’ input of the meter to the ‘ground’ jack. Use a red banana-plug lead with the ‘V’ input of the meter.
(a) An arbitrary circuit diagram is shown as an illustration of how to use a voltmeter. Note that the meter measures the voltage drop across both the resistor and capacitor (which have identical voltage drops since they are connected in parallel).
(b) A drawing of the same circuit showing how the leads for a DMM should be connected when measuring voltage. Notice how the meter is connected in parallel with the resistor.
(b) A drawing of the same circuit showing how the leads for a DMM should be connected when measuring voltage. Notice how the meter is connected in parallel with the resistor.
