Multimeters

They sound kind of boring but are actually an important use in real life. Well its important if you're an electrician and actually know how to use it or care to learn to use it. Mechanics also use these to check the electrical of cars and other motorized vehicles. We use the multimeter to measure the "voltage across" and the "current through" something. When measuring current you must break the circuit and insert the two probes in the hole to complete the circuit again.  Some real life situations that a multimeter can be used for are things such as to check for a broken wire or bad plug connection in an extension cord or in any outlet of the house. If it isn't working you can use the multimeter to see what wire is a defect and what the problem is.