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It is impossible to online buy a cheap Non-contact Direct Current voltage tester pens.

z234

Dear friends,

I found it is impossible to online buy a cheap Non-contact Direct Current voltage tester pens.

They only sell AC pens.

Does anyone know where to buy cheap Non-contact Direct Current (DC) tester pens , that is not those very expensive Fluke pens?

Thanks for all your great help and May God bless you and your family Two hearts Pray

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    In general, AC emits alternating magnetic fields which are easy to measure and radiate some distance. By contrast, DC emits a static magnetic field which is much more difficult to detect and measure as there are many competing sources of noise (e.g. Earth's magnetic field, remnant magnetism in cores/metals, etc). As a result, such a detection capability is not trivial - an AC tester could just use a regular coil of wire on a core like an inductor while a DC tester would need a very sensitive hall-effect sensor and a core that has little remnant magnetism to have any chance of working. Perhaps it would be hard to know the difference between a weak fixed magnet and a wire with DC flowing through. Worse still, this static field gets very small when the current flow is small - typical of low-voltage circuits.

    For the same physically-related reason, DC clamp meters are more expensive than AC clamp meters because they are simply more difficult to realise and be accurate.

    Sorry, but I don't think you will find cheap non-contact DC voltage detectors ... furthermore, such test devices are really only good for tracing things through walls as a rough indication and can't be relied on to make a good reading of voltage - for safety, you MUST measure the voltage by contact means and confirm.

    - Gough

  • 0 in reply to Gough Lui

    Very grateful for ur reply.

    I researched that ac alternatives and the capacitance coupling allows the light n sound of ncvt testers while DC is constant current n can't.

    Thanks very much 

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