Today we bring you an experiment based on the RC Oscillation Detection circuit. Would you like to know if there is an AC Voltage across a wire in your home? You can do this using a contactless voltage detector. So, the design needs very few components and only 3 transistors. It is very portable and power consumption is also very low.
Let’s get started with the design.
Perform this experiment under adult supervision if you are under 16.
- BC547 – 3 Pieces
- LED – 1 Piece
- 220 Ohm Resistor – 1 Piece
- 22AWG Copper Wire
- 9V Battery with Connector
Watch the Video to Build A Contactless Voltage Detector
Steps to Follow
- Connect all the Collectors of the 3 BC547 Transistors together.
- Connect the Emitters of each BC547 transistor to the base of the other. This configuration is also known as Darlington Transistor Array.
- Connect the positive of the Buzzer to VCC. Connect the negative of the buzzer to Collector.
- Make the antennae from a single core wire with approximately 5-10 Turns. If your supply voltage is 120-160V, you require 8 turns.
- Connect the 9V Battery with Power Socket. The Emitter is connected to the negative and the positive of Buzzer will be connected to the VCC.
Now if you’re wondering how to use a voltage detector, simply bring the antennae near a live electric supply. The buzzer shall ring if the device wiring was done properly.
We hope you enjoyed building this non-contact voltage detector using BC547 transistors.