Electricity makes life better: it powers appliances and automobile, and bends the extremes of hot and cold toward a bearable, warm mean. It's a beloved friend that can harm or even kill if not respected fully. Extra care is in order when working with electricity; you should never guess whether an electrical component is live. A circuit tester is an inexpensive, simple-to-use tool used to test for the presence of electricity. Every do-it-yourselfer should own one.
Hold the plastic, insulated end of the tester in one hand and the clip in the other.
Attach the clip end to a nearby piece of metal.
Touch the pointed end of the tester to a fuse, relay, wire or switch. The light in the tester will glow if it detects electricity in the circuit; it will remain off if no electricity is present.
