How to make an electrical continuity tester

When working with electrical circuits and appliances, it is advisable to have a tool that allows us to verify if the appliance or circuit is working correctly, or if it is receiving power. This tool is called an electrical continuity tester, and it emits an alarm to show the user that the circuit is working correctly. Next, we will see how to making an electrical continuity tester with few materials and in a simple way so that they don't have to search in the yellow pages a technician to do it for you.

Electrical continuity tester


- One 9 V battery.

- A 1 KΩ resistor.

- One LED.

- Conductor cable.

- Crocodile type connectors.

- A piece of wood or plastic.

Assembling our electrical continuity tester

We start the assembly of our electrical continuity tester by fixing the battery to the piece of wood or plastic with the help of a silicone or glue gun.

electrical continuity tester

Once we have fixed the battery, it is time to make a connection with the help of a tin soldering iron, between one of the ends or poles of the battery, using wire up to the resistor. Then, the free side of the resistor is connected to one of the poles of the LED, and the other pole of the LED is connected to one of the crocodile type connectors (red connector).

Now it is time to complete our device. To do this, we make a connection from the free pole of the battery to the black crocodile connector. In this way, we will have completed the assembly of our device, it only remains to test it. To do this, we must place the connectors in different points of the circuit to test and we will be able to visualise its operation.

tester circuit

How it works

When we connect two points of a circuit to the crocodiles, the internal circuit of the device is closed. When we do this, the Led light comes on, indicating that indeed, it is present. electrical continuity on the device to be tested.

11 thoughts on “Cómo hacer un probador de continuidad eléctrica”

  1. Epale compa , and it will also work with a 6v rechargeable battery ? And how to make a charger to recharge said battery ? Regards

  2. wiliiam angulo

    Thank you. Companeros for the excellent, simplified and very detailed information. I found it very helpful.

  3. aaaron ramirez

    that if the circuit where continuity is tested has a higher voltage than that of the continuity tester

  4. frank eduardo centeno

    we can also add a sound sensor, I have made a homemade capacitance meter but designed in 110 volts and it gives me more accuracy than the 220 volts capacitance meter, apart from the ease of use because anywhere we can find a 110 volts point.

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