Continuity tester
A continuity tester is an electrical test device that uses an optical or acoustic signal to indicate whether two points are electrically connected to one another.
Continuity testers can be used, for example, to check the correct wiring of an installation or to find faults in an existing installation.
A continuity tester consists of two test probes , between which it generates a harmless auxiliary or test voltage (usually 1.5 to 4.5 volts) using a built-in battery . In series with this there is a signal lamp ( incandescent lamp or light-emitting diode with series resistor) or an acoustic signal transmitter in the device. If there is an electrical connection between the test probes, a current flows which the test device signals optically or acoustically.
Continuity testers are often designed in the form of a thick pen and have one of the test probes permanently attached to one end. The second test connection is partially equipped with an alligator clip so that you can work with one hand.
Also, resistance measuring instruments can be used as a continuity tester, they often have in addition a continuity tester function, in which they produce a signal falls below a certain resistance value. Depending on the model, however, a delay can occur, which is why the measuring tips of such devices must be very consciously placed on the route to be tested.
Since the auxiliary voltage is a direct voltage , a continuity tester can also be used to test diodes , provided that their forward voltage is lower than the test voltage (battery voltage).
See also
literature
- Horst Frey, Jens Uetrecht, Georg Walz: The great electrical home improvement book , Franzis Verlag 2003, ISBN 3-7723-5200-6