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Non-Contact Voltage Detector: Electricity can cause injury or even can become the cause of death which is why safety must come first when working with electrical devices or electricity. In this article, we will show you how to design a simple efficient Non-Contact Voltage detector by using transistors. You can build this circuit by using simple components and testing the presence of AC voltages. You need not worry about getting zapped because it is a noncontact voltage tester.
In this modern age almost everything we use with an electric current. Before working with the AC object we must verify that the current is not present where we work. So we use the tester, A non-contact voltage tester is a safe way to make sure that the AC power is off.
In this project, we have designed a very simple Non-Contact Voltage Tester Circuit by using transistors. we have used only one type of transistor in this project.
| Qty. | Part Description | Mfr. Part No. |
| 3 | Transistors | BC547 (NPN) |
| 1 | LED, Red | or any color |
| 1 | Buzzer (optional) | 3v |
| 1 | Switch | any type |
| 1 | 9V Battery or 3v can be used also | or supply |
| 1 | Battery Snap | |
| 1 | Case any plastic cover | plastic cover |
Required Tools:
Soldering Iron
Solder
Drill and drill bits (for making holes in the box)
Copper Wire
Cutters (for copper wire)
Adhesive Tape
Make an antenna with a small piece of copper wire and is connected it to the base of the first Transistor (BC547). The antenna detects the magnetic field when we placed it near AC objects like cables and switches and etc, it gets a small amount of current and activates the first transistor through the base.
The output of the first transistor drives the second transistor, it gets activated and the third transistor is activated with 2nd transistor's output. As the third transistor activates, the LED is turned ON.
We can use a small buzzer in place of an LED. The buzzer will alert you through voice, Buzzer should be 3 volts because we are using a 3v battery.
Thank you so much for visiting our website if you have any questions about this circuit or any circuit about electricity or electrons you can discuss them freely.