Voltmeter
The voltmeter can be connected by joining two wires to where the voltage is. One wire is the positive one, and the other the negative. With some voltmeters, one must make sure that the wires are connected to the right spots: the positive connection on the voltmeter to the more positive "part" of the voltage source, and the negative to the more negative "part". This way, the voltmeter is parallel to the electrical circuit.