A non contact voltage tester is a very import tool in the field of electronics. This post is about few non-contact voltage tester circuits for checking the presence of main supply. We will be know in detail what non-contact voltage tester/detector, functions and how to make one using transistors.
What is non-contact voltage tester
Non-contact voltage tester or detectors are AC tester that can be used to check the presence of electricity without touching the wires. Mostly used voltage tester has metallic tip to touch physically for the presense of Main supply. A Non Contact Voltage Tester or detectors is very safe to test AC. So, it reduces the risk of electric shocks while working at high voltages like 220v or 110v.
Tis tester has antenna for picking up the leakage current on main wires. The leakage current flow through nob/antenna and fed to very high gain output. The amplifier goes high when it detects weak electrical signals. The amplified voltage can be applied on buzzer or LED to show the physical signlas. It is always good idea to carry a traditional voltage indicator along with non-contact voltage indicators.
Practical video
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