Electromagnetic field sensor circuit
Notes.
This is a very simple circuit that can be used to sense electromagnetic radiations. The circuit can even detect hidden wrings. A 1mH inductor is used for sensing the electric field. The electric field will induce a small voltage in the sensor inductor and this induced voltage is amplified by the opamp.The headphone connect at the output of the opamp will give an audio indication of the electric field. For example, the electric field around a mains transformer can be heard as a 50 Hz hum. The POT R4 can be used to adjust the gain of the amplifier. By keeping the sensor inductor near to a telephone line, you can even hear the telephone conversations.
Circuit diagram with Parts list.
Notes.
- Assemble the circuit on a general purpose PCB.
- The circuit can be powered from a 9V PP3 battery.
- It is better to have a radial type inductor for L1.
- The POT R4 can be used to adjust the gain.
- The switch S1 can be a slide type ON/OFF switch.
- The IC1 must be mounted on a holder.
- All electrolytic capacitors must be rated at least 15V.
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how to calculate the voltage applied on pin2 and 3 mathematically? By using formula’s
Where can I find a 2.2 m pot at R4?
1) how i test to ckt?
2)can i replace led for hp?
3)can u show me which terminals of pot i can short?
Hi Naik the inductor picks up the stray magnetic field available in its near visinity and amplifies it through IC 741, which is a variable gain amplifier and feeds it to the head phone for listening. will be useful for finding the route of consealed power wiring at home by listening to 50 / 60Hz power supply frequency.
i want to know how this ckt actually works?
I want ask can I test leak from microwave oven.
Thx a lot it worked really well,Can i use led in place of speaker?
sir,
i want to ask that radial inductor is not available in my region then there is any other alternative for that…….can you please tell me…..
can you explain the circuit. and what kind of opamp in there? is it e differentiator?
what should i changes if i want to increase the detection frequency until 6Mhz?
thx