A circuit tester is an electrical device commonly used to test if power is present in household electrical circuits, which are typically rated at 110 volts in the U.S. Circuit testers are easy and simple to use, but are critical tools for anyone working with electricity. A simple circuit tester has two probes wired to a light that will illuminate to indicate the presence of power. A homemade circuit tester is relatively easy to build, but circuit testers that are commercially sold are very inexpensive and can easily be found in hardware stores.
A homemade circuit tester should be assembled using parts that are rated according to the voltage of the circuit being tested; thus, a 110-volt circuit tester should have a receptacle, wires and a bulb which are rated at 110 volts. Building a tester using electrical components rated below the voltage of the circuit being tested can damage the tester and the circuit being tested, and can result to injury.
Materials Needed to Build a Homemade Circuit Tester
Building a simple 110-volt circuit tester requires a 110-volt light bulb, a pigtail light socket, electrical tape and two pieces of 6-inch 14 gauge AWG solid-copper wire. The 110-volt light bulb will indicate the presence of power. The pigtail light socket will allow a means of connecting the wires to the bulb. The two pieces of solid-copper AWG wire will act as probes. Wires protruding from the top of the socket will provide connectivity between the socket and the probes.
How to Assemble a Homemade Circuit Tester
Assembling the 110-volt circuit tester is an easy task. Both ends of each 6-inch solid-copper wire should be stripped of insulation about an inch deep, using a wire stripper. One end of each solid copper wire should then be spliced to the end of each wire running from the top of the light socket, using regular pliers. After splicing the wires, each connection must be completely insulated by covering each with several rounds of electrical tape. Finally, the light bulb must be screwed into the light bulb socket.
How to Use the Homemade Circuit Tester
Hold one probe in each hand by the insulation and insert the bare copper tip of each probe separately into each slot on the 110-volt outlet in any order. If the tester bulb lights up, the circuit still has power. Homemade circuit testers are easy to make and convenient to use, but they are not a substitute for a multimeter.