How to Make Your Own Emf Detector || BJT As a Switch

We can sense voltage in a circuit using a multimeter by connecting two probes at two different point in a circuit ie basically contact voltage detector.

As far as the era is concerned there also exist Non contact voltage detector. You can simply buy one,but that will be too boring for an electronics enthusiast.

Step 1: Link for the Video.

Go check out the tutorial for more clear instructions and the build.

Step 2: Parts List.

The parts list for this project is very simple any easily available.

Amazon.com

1.BC547-https://goo.gl/Z5hHPH

2.1M ohm resistor-https://goo.gl/vc0DFA

3.100K ohm resistor-https://goo.gl/vc0DFA

4.39K ohm resistor- https://goo.gl/vc0DFA

5.5mm Red led-https://goo.gl/s0Xzai

6.9V battery and battery connector

Step 3: Connections and Circuit Diagram

The circuit for emf detector has 4 transistor connected in cascade form. Connecting transistor in cascade form helps the gain to increase.The overall gain is the product of individual gain of each transistor which inturn lights the led.

Its always a good idea to build a circuit on a breadboard.