How to Make Polarity Tester Circuit

Hii friend,

Today I am going to make a circuit of Polarity tester that which we can use to check the polarity of any DC Power supply upto 12V DC.The power supply can be of battery, Charger, Rectifier etc.We can check polarity easily using this device.

Let's get started,

Components required -

(1.) Buzzer x1

(2.) Probes x2 {+ve and -ve probe}

(3.) Zero PCB

(4.) Resistor - 1K x1

(5.) LED - 3V x2 {Red LED for wrong indication and Green LED for write indication}

(6.) Battery {Source for testing the Polarity}

This is the circuit diagram of this project {Polarity Tester}.

Assemble all components on zero pcb according to this circuit diagram and solder the pins as given in the circuit diagram.

Firstly Insert Both LEDs {Red LED and Green LED} on the PCB as inserted on the picture.

Polarity of both LEDs should be opposite to each other as given on the circuit diagram.

Next Solder the pins of LEDs as shown in the picture.

Next we have to connect 1K Resistor to the circuit.

Solder 1K Resistor with the LED as given on the circuit diagram.

Next Connect the Buzzer.

Solder pins of the buzzer in parallel with LEDs including 1K Resistor as given in the circuit diagram.

Now we have to connect the wires of buzzer.

Solder wire of +ve probe to +ve pin of the buzzer and

Solder wire of -ve probe to -ve pin of the buzzer as given on the circuit diagram.

As above picture shows when I connected the +ve probe to -ve terminal of battery and

-ve probe to +ve terminal of the battery then Red LED is glowing and Buzzer giving sound.

Now as above picture shows when I connect the +ve probe to +ve terminal of battery and

-ve probe to -ve terminal of battery then Only Green LED is glowing.

It means the polarity of this DC Source is correct.This type we can find easily +ve and -ve terminal of any DC source upto 12V using this device.

Thank you