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What are the parts of a voltage detector?

What are the parts of a voltage detector?

Shop for Voltage Testers

labelled parts of non contact voltage detector

The design of voltage detectors are fairly standard across all manufacturers. The parts of a voltage detector include an on/off button, a body for holding and the nose or probe that is used for identifying voltage. Read our full guide below on the different parts of a voltage detector to learn more about what each section does.

Voltage detector body

square, round, flattened non contact voltage detector bodies The body of non-contact voltage detectors consists of a simple plastic shell which houses the electronic circuit that powers the tool. The body also doubles as the part of the tool that you hold. It is generally cylindrical in shape but can be square or a slightly flattened version of a cylinder or square.

Voltage detector nose or probe

non contact voltage detector nose/ probes The nose or ‘probe’ on a non-contact voltage detector tapers like a pen/pencil and has an extended tip for better probing. This part of the tool houses the sensor which does the detecting. The tip is the correct size and shape to be inserted into plug sockets.

Voltage detector on and off button

non contact voltage detector on/ off button The on/off button is positioned at the top end of the tool or on the body. It is usually a simple press-down button which may require a quick push or holding down for a few seconds, and you should consult the user manual to find out how to use your specific detector.The buttons on the body of the tool are thought to be slightly more convenient, as they are less likely to be knocked on in your bag or pocket.
voltage detector going off in pocket It is possible for voltage detectors to not have an on/off button and remain on at all times. The battery on these types will run down quicker and they may also be activated by stray charges when not in use, making them less reliable than those with an on/off button.

Alternative voltage detector shapes

voltage detector/ power detector There are alternatively shaped voltage detectors which are more square and do not have the pen shape, with tapered tip. They work in the same way and the differences are minimal, but they are rarer. The pen shape is generally favoured because it is slightly handier to hold, store and transport.

Additional voltage detector features

non contact voltage detector sensitivity sclae

Sensitivity scale

Each non-contact voltage detector will have a range of voltages it is suited to detect. It is possible for these ranges to be fixed or adjustable. Adjustable voltage detectors will be equipped with a turning dial which allows you to adjust the sensitivity of the tool and the detectable voltages.

voltage detector sensitivity As non-contact voltage detectors actually detect electromagnetic waves, the sensitivity scale is more to do with the distance from the source at which the tool will pick up electromagnetic waves, than the actual voltage levels. Increasing the sensitivity means that the detector will be able to sense the electromagnetic waves further away from the electrical source and decreasing it will require the device to be closer.
low voltage detected However, the voltage levels do affect this, as a lower voltage would produce less electromagnetic waves and so the sensitivity would need to be turned up higher at a shorter distance than compared to a higher voltage source.
non contact voltage detector torch


Some non-contact voltage detectors have a small built-in light or torch, which can usually be found either at the probe-end or at the top of the tool. The torch will usually be made up of LED bulbs and operated by a button on the body of the device. These are helpful when working in poorly-lit areas.

non contact voltage detector battery checker

Battery checker

A battery checker is a very beneficial feature on non-contact voltage detectors, and consists of a simple button which tests the battery life of the tool before you use it. Usually, a working battery will be indicated by a light when the button is pressed.

non contact voltage detector clip


To complete the ‘pen’ look, many non-contact voltage detectors have a clip at the top for hooking the device onto things like pockets.

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