How to use an electrical testing screwdriver.

Voltage tester screwdriver
Voltage tester screwdriver

Knowing how to use an electrical testing screwdriver is a skill that is essential. This tool helps a lot when you want to check voltage at home.

Before I can go ahead and show you how to use an electrical testing screwdriver, I would like you to know the parts that make up a tester screwdriver.

Parts of an electrical testing screwdriver.

A tester screwdriver is made up of the following parts.

  1. Metallic rod
  2. The sheath of the plastic insulator
  3. Metallic screw cap
  4. Neon lamp
  5. Metallic Spring
  6. Resistor

How do these parts work?

Metallic rod.

This is the conducting part of the tester screwdriver. It is the part that makes contact with the cable or area that you want to measure.

A sheath of plastic insulator.

The plastic sheath is an insulator that covers part of the metallic rod and the entire tester screwdriver. An insulator protects you from accidental electric shock.

Metallic screw cap.

This is where you put your thumb to complete the circuit when you are checking your voltage with the tester screwdriver. This is the path to the ground through your body.

Neon lamp.

A neon lamp is an indicator,it is that part of a tester screwdriver that glows when it detects current or voltage.

Metallic spring

A metallic spring act as an earth wire ,it is a link between the metallic rod and Metallic screw cap.


A resistor is an electrical device that resists the flow of electric current. A resistor does this by allowing the set current to pass through it.

In a tester screwdriver, the resistor reduces the current that passes through our bodies to make a complete circuit. You might be wondering, why you don’t get an electric shock when you are using a tester screwdriver.

A resistor used in a tester screwdriver has a very high resistance to the flow of current such that it allows a small amount of current in milliamps. usually 10mA or less.

How to use a tester screwdriver.

  1. You hold a tester in one hand,the you touch the point you want to test with the tip of the tester screwdriver.When you touch the point you want to measure, you place your thump on the metallic screw cap.This will complete the circuit.When current or voltage is present,the the neon lamp will glow.
  2. When no voltage is present ,the neon lamp will not glow.It is important to note that at time the neon lamp will glow if it detects a leakage of current.Then how do you differentiate the glow for normal voltage and that of leakage voltage.The normal glow is bright while the glow for leakage current is faint.
  3. For you to take a correct reading for the tester voltage,you first test a circuit that you know is OK.Thats when you go ahead and measure a faulty circuit.

When do you use a tester screwdriver.

A tester screwdriver is not a tool that will give you the exact voltage that is flowing in a circuit or the current.A tester with a neon lamp,is handy when you want to know that there is voltage in the circuit.

It is there to show you that there is voltage.It is not able to tell you how much voltage is present.In an instance that there low voltage,a neon tester is not going to show you that there is low voltage.

When you want to know the value of either current or voltage, you use a multimeter.A multimeter is going to give you the actual value of voltage and current.Therefore,if you are suspecting low voltage,you need multimeter for this.

Gardner bender combination voltage & continuity tester screwdriver.

This is a handy tool to use when you don’t need a multimeter.


  • You can test 12-250v AC/DC on an energized circuit.
  • It has an LED indicator lamp that glows when either voltage or continuity is detected.
  • You can use this tester on wall socket outlets,fuses,switches,extension cord,light fixtures and low voltage circuits.
  • It has a convenient screwdriver tip and pocket clip.


  • It’s a contact tester screwdriver you have to touch the point where you are testing.
  • The battery holders are not very robust,they can be loose at times thought it can easily fixed.
  • There is no way to change the LED lamp when it burns out.

Place to buy: Here

My thoughts on this tester,screwdriver.

I think it is a good tool to have at home.Especially when you want to know the continuity of a wire or any appliance in the home.There is no need for you to start selecting the correct meter to use like in a multimeter.

Do I recommend Gardner and Bender tester screwdriver? Yes I do .Have you used this tester screwdriver? You are free to share your experience using Gardner Bender Voltage screwdriver in the comments section.

conclusion on how to use an electrical testing screwdriver.

A tester screwdriver is a very useful tool when you are doing simple electrical trouble shooting. Like when you want to know whether voltage is present or not.

There are situation in electrical and electronics diagnostics,when you need the actual values of voltages and currents for you to do proper analysis of the problem or fault at hand.A tester screwdriver can’t give you the actual values that you need.A mulitimeter can.

All in all every tool has it’s place in electrical trouble shooting.What is important to know is that where capabilities of one tool ends,there is another tool that can solve the limitations of the other tool.

Know what you want to measure then select the correct tool or instrument that can do the task for you.

Share your experience using voltage tester screwdrivers in the comments section below.

How to use an electrical testing screwdriver.

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