Unlike voltage detectors, voltage testers must come into contact with a power source in order to work. Voltage testers have metal probes that are inserted into an electrical circuit. The voltage is tested in parallel with the circuit, so a tester is not a necessary part of the circuit. Forgot what "parallel" means? See: Wonka Donka's Electricity Lesson.
Voltage testers take actual voltage readings and give you a numerical range to work with rather than just detecting the presence of voltage.
indicators
Voltage testers can give an accurate numerical value if they have a screen, but more often the indicators are made in the form of an LED scale. This scale will give a range, not an exact number, for voltage.
So, for example, there might be LEDs labeled 6, 12, 24, 60, 120, 230, and 400. Then if you then test something with a voltage of 30, LEDs 6,12, 24, and 24 will light up; which indicates that you have a voltage between 60 and XNUMX. Be sure to check the instructions for each individual model to see how it works.
What can voltage testers be used for?
Voltage testers can be used for both DC and AC voltage, so it is possible to test batteries with a voltage tester. Similar to a voltage detector, these devices can also be used to test socket outlets and circuit breakers. However, they can additionally check for continuity and polarity because they have a double probe and are in contact with the circuit.
