Voltage Detector Using BC547 Transistor

Introduction: Voltage Detector Using BC547 Transistor

About: Share diy projects to those who have the same hobby with me

Hii friend,

Today I am going to make Voltage detector circuit using BC547 transistor.This circuit is very sensitive and it is good project to detect voltage.

Let's get started,

Step 1: Take All Parts As Shown Below

Components required -

(1.) Transistor - BC547 x3

(2.) Buzzer x1

(3.) Copper wire x1

(4.) LED - 3V x1

(5.) Battery - 9V x1

(6.) Battery clipper x1

(7.) Resistor - 220 ohm x1

Step 2: Solder Two Transistors Like This

BC547 -

pin-1 is collector , pin-2 is base and pin-3 is emmiter -

solder collector pin of one transistor to another and

base pin of 2nd transistor to emmiter pin of 1st transistor as solder in picture.

Step 3: Next Connect All Three Transistors As Picture

Next solder all three transistors as solder in the picture.

Solder collector pin of 3rd transistor to collector pin of transistor 1 and 2

and solder base pin of 3rd transistor to emmiter pin of transistor-2 as solder in picture.

Step 4: Next Solder LED and Resistor

Solder -ve pin of LED to common collector of all transistors -

Now connect 220 ohm resistor to +ve pin of LED as connected in picture 2

Step 5: Next Connect Resistor

Next solder +ve pin of buzzer to resistor as solder in picture.

Step 6: Connect -ve Pin of Buzzer

Next connect -ve pin of buzzer to collector pin of all transistors as shown in picture.

Step 7: Connect Battery Clipper Wire

Next connect battery clipper wire to the circuit as solder in picture.

Solder +ve wire of battery clipper to +ve of buzzer and

-ve wire of battery clipper to emmiter of 3rd transistor.

Step 8: Next Solder Copper Wire to Circuit

Next solder copper wire to base pin of 1st transistor as shown in picture.

Now Voltage detector circuit is ready , let's check it.

Step 9: How to Use It

Since circuit is completed.

Connect battery to battery clipper and check AC line.This circuit will detect phase wire and neutral wire.

Buzzer will give sound and LED will glow when copper wire of this circuit will be in the near of passing current phase wire.

We can easily detect phase wire and neutral wire of household wiring.

NOTE 1 : We don't have to touch circuit / copper wire of circuit to the surface as you can see in the picture.Because this circuit is very sensitive.

NOTE 2 - If your circuit is not working then please change transistors.

Above picture -

Above pictures shows when I put this circuit near current flowing phase wire then Buzzer is activated and give sound and LED is starting glow.

and when I put it near to neural wire then It's circuit is not activated.

If you want to make more electronic projects like this then don't forget to follow utsource.

Thank you

Be the First to Share


    • The 1000th Contest

      The 1000th Contest
    • Battery Powered Contest

      Battery Powered Contest
    • Hand Tools Only Challenge

      Hand Tools Only Challenge

    3 Discussions


    7 weeks ago

    What resistor should i use if i wanted to add one more transistor to make it more sensitive


    Question 9 months ago

    function of transistor,resistor,does it works for dc