How to Test An Electronic Ballast With A Multimeter-Easy and Simple Guide

It is a real blessing to have basic electrical knowledge. Because you have to deal with a lot of electronic devices. Today, we will learn how to test an electronic ballast with a Multimeter.

A ballast is an essential part of fluorescent light. If it fails, your light cannot work. So, it needs to be checked and fixed. The process is very simple. So, let us begin.

What is An Electronic Ballast?

An electronic ballast is attached to the lights. It is placed in a series within a circuit. Its function is to control and regulate the amount of current passing through it.

It provides only the required power to the light. If the light is connected directly to the high voltage, it will draw current uncontrollably. Resultantly, the lights will burn out.

Hence, the ballast acts like a stabilizer. They are of many types depending upon the type of fluorescent light. The common types include preheating, rapid start, instant start, emergency, dimmable, and hybrid. They are purpose-specific.

What is A Multimeter?

A Multimeter is used to measure the electrical values. For example, it measures AC/D


C, current, resistance, and voltage. It has the following parts;


Display: The digital display shows values and results in numbers.

Buttons: It also has many buttons featuring different options.

Dial Knob: It has values around it. The dial is used to set the measurement protocol or value.

Input Jacks: The input jacks are for connecting testing leads or sensors.

A digital meter is more efficient and easy to operate than an analog model. Moreover, it is durable and accurate with no parallax error. However, it is expensive.

How to Test An Electronic Ballast With A Multimeter-Easy and Simple Guide

Types of A Digital Multimeter

It comes in three types. The basic purpose of all types is the same. But, they differ in some advanced features.

Fluke: It is the most basic version. In other words, Fluke is the digital version of the analog model.

Clamp: It is an advanced type in terms of measurements. It measures the current without plugging directly onto the conductor.

Auto-ranging: As the name suggests, it detects the settings automatically. It is the most advanced version.

Learn to Test the Ballast with A Digital Multimeter

Now, you have knowledge about the multimeter, its structure, types, and operations. Hence, we can learn to test easily. Here is the step-by-step guide;

Tools You Need

Following are the important tools you need for checking the ballast.

  1. A digital or analog multimeter.
  2. Rubber, latex, or any sort of gloves to protect both your hands and lights.
  3. A screwdriver. It is required to unscrew the ballast from the fixture.

Step 1: Switch OFF Power

Turn OFF the power supply to your electronic ballast. You can do it at the circuit breaker or the power switch linked to the light.

Step 2: Remove the Light

Next, remove the light from its socket or fixture. It is better to put on gloves so that your lights do not damage.

Because your skin oil can transfer on a light surface. It will leave marks and will decrease the efficiency of the light.

Step 3: Uninstall the Ballast

To test the ballast, you have to uninstall it from its housing. Remove its cover plate. Unscrew it using the screwdriver. Disconnect the wires joined with the ballast. White, red, blue, and yellow wires linked to it.

The white wire is the ground wire. Do not forget to label them. Otherwise, you will connect wrongly while reinstalling. Remove the ballast completely from the base pan.

Step 4: Examine the Ballast

Before testing, you should examine the ballast apparently. Oil or liquid leakage indicates that the ballast has ruptured and failed.

Its seal has gone and the internal components have melted. Too much rust also indicates failure. Such a bad condition is clear evidence of damage.

Step 5: Test the Ballast

Set your digital multimeter at 1000 ohms “Ω” resistance. Locate the white ground wires on the ballast. Now, connect the back lead/prong of the meter to the white ground wires.

Meanwhile, connect the red lead of the meter to the yellow wire. Notice the reading. Likewise, connect the black lead to the ground wire and the red lead to the blue wire.

In fact, you have to test the ground wire against each other wire on the ballast. So, keep the black prong on the white wire and test all the other wires with the red lead one by one.

Step 6: Understand the Test Results

Low resistance on the display shows that the ballast is bad. For example, 0.04 or 37 ohms is not good reading. If it displays “OL-open-loop”, maximum resistance, or value “1”, the ballast is good.

A current reading between the ground wire and the rest of the wires confirms faults. This reading indicates that no current is traveling between the ground wire and the other wire.

Visible Signs of a Bad Ballast

Some signs clearly indicate that the ballast has gone wrong. You can identify them by observing them;

  • Flickering of fluorescent lights.
  • Delay in the start. The light takes longer to start ON or reach full brightness.
  • The light glows dim and never reaches full brightness.
  • Buzzing, humming, or other weird signs from the light.
  • The cover of the ballast is swollen or ruptured. Oil or liquid leakage.
  • Inconsistent lighting or dark corners/areas in the fluorescent light or bulb.

FAQs About Electronic Ballast

Read the following frequently asked questions for more information. Freely ask in the comment box if you have further queries.

Why an electronic ballast goes bad?

Overheating is the major cause. Extreme weather conditions, direct exposure to heat, and internal circuit heating lead to overheating. Moreover, moisture and water contact causes corrosion. However, electrical problems and faults can also cause failure.

What is the voltage output of an electronic ballast?

A fluorescent ballast is either 120 volts or 230 volts. The ballast with 120V output is used in homes. While the higher voltage (230-550) is used in commercial setups. The voltage output varies and depends on the types of lights.

What is the difference between an electronic and magnetic ballast?

A magnetic ballast has copper coils that produce the magnetic field. The coil stores the current and then send the required amount to the light. It operates at a 60Hz frequency. In contrast, the electronic ballast works at 20,000 Hz. It converts AC into DC. The basic purpose of both types is to store, control, regulate, and supply the needed power to the fluorescent lights.

Also Go Through: Change 2 Pin Fluorescent Light Bulb-Ultimate Solution

Final Thoughts

As you learned, it is very simple to test an electronic ballast with a multimeter. Maybe you feel confused at first. However, you should learn this basic checkup. A multimeter helps you test all electronic devices. I congratulate you on learning a new thing today!

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