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what is in an electronic ballast

by Shanna Davis Published 2 years ago Updated 1 year ago

Basic Circuitry of an Electronic Ballast

  1. EMI filter: Blocks any electromagnetic Interference
  2. Rectifier: Converts AC power to DC power
  3. PFC: It does Power Factor Correction
  4. Half-Bridge Resonant Output: Converts DC to square waved voltage with high frequency (20 kHz to 80 kHz).
  5. Control Circuit: Controls voltage and current across and through the lamp respectively.

An electronic ballast uses solid state electronic circuitry to provide the proper starting and operating electrical conditions to power discharge lamps. An electronic ballast can be smaller and lighter than a comparably rated magnetic one.

Full Answer

How does an electrical ballast work?

How Does an Electric Ballast Work? A ballast stabilizes the current through an electrical load. The most common use is within an electrical circuit or a device that presents a negative resistance to the source. If this device was to be left connected to a constant supply of voltage, it would gradually draw more and more power until it could not ...

What is an instant start electronic ballast?

Instant start. An instant start ballast does not preheat the electrodes, instead using a relatively high voltage (~600 V) to initiate the discharge arc. It is the most energy efficient type, but yields the fewest lamp-start cycles, as material is blasted from the surface of the cold electrodes each time the lamp is turned on.

How to test an electronic ballast with a digital multimeter?


  1. Connect the digital multimeter between the power source and the ballast.
  2. Turn on the ballast.
  3. Measure the voltage output of the ballast with each of the three probes on your digital multimeter.

How many Watts Does a fluorescent electronic ballast use?

They consume eight to 10 watts when operating with the lamp in the circuit. The ballast will consume about four watts when the lamps are removed although the ballast is still energized. Electronic ballasts start and regulate fluorescent lamps with the use of electronic components.


What is inside an electronic ballast?

A magnetic ballast (also called a choke) contains a coil of copper wire. The magnetic field produced by the wire traps most of the current so only the right amount gets through to the fluorescent light. That amount can fluctuate depending on the thickness and length of the copper wire.

Do electronic ballast have PCBs?

The PCBs are contained within the light ballasts' capacitors and in the ballasts' potting material, which is used for insulation. Until the late 1970s, PCBs were commonly used as insulators in electrical equipment because they have high tolerance to heat, do not burn easily, and are non-explosive.

What is the black stuff in a ballast?

PCBs are contained within the light ballasts' capacitors and in the ballasts' potting material (a black tarlike substance used to protect the capacitor). As the ballast ages, it can overheat causing a burning or smoky odor or in some cases, causing tar from the potting material or oil to drip from the fixture.

Do light ballasts contain mercury?

This is important because lamps and certain ballasts contain hazardous materials, such as mercury, which can contaminate the environment and is harmful to human health. Each fluorescent lamp contains around four milligrams of mercury, which means one thousand fluorescent lamps contain four grams of mercury.

Are old light ballasts worth anything?

Depending on their age, and their casing, even if they have to be scrapped, ballasts can be worth a couple of dollars. According to current listings, if you can resell one that's in fantastic condition, you can often get $13 to $20 for the average ballast! These are ones in great condition.

Can light ballast be thrown away?

The entire lighting fixture does not need special handling and disposal as long as the ballast (electrical box) is not leaking. The non-leaking ballasts can be removed and recycled or disposed of properly.

Is ballast toxic?

Magnetic ballasts made prior to the late 1970s contain highly toxic polychlorinated biphenyls (PCBs). Doing the right thing from an environmental standpoint generally means incorporating fluorescent lighting into our buildings.

Do electronic ballasts get hot?

Ballasts usually run hot, about 140 degrees F, but if one is so hot that you can't keep your hands on it, it is likely the culprit.

Do ballasts store electricity?

A ballast is like a capacitor. Think of a ballast as a short-term battery. It stores power then releases it as needed. A common example of a ballast is on fluorescent lights.

Are fluorescent light ballast hazardous?

Fluorescent lighting ballasts contain mercury and some contain PCBs (Polychlorinated Biphenyls), which are both considered hazardous and therefore illegal to dispose of with regular trash.

When were PCB ballasts banned?

1978The Environmental Protection Agency (EPA) banned the manufacture of PCB in 1978. Thus, all light ballasts manufactured thereafter should not contain PCB.

How do you dispose of fluorescent tubes?

All fluorescent lamps and tubes must be recycled, or taken to a household hazardous waste disposal facility, a universal waste handler (e.g., storage facility or broker), or an authorized recycling facility.

Do T8 ballasts contain PCB?

Only the T12 magnetic FLBs (not T8 or T5 FLBs) may contain PCBs.

What is the difference between electronic ballast and magnetic?

While magnetic ballasts in fluorescent lamps work at a frequency of 60hz, electronic ballasts greatly increase that frequency to 20,000hz.

What is electronic ballast for fluorescent lights?

ballast - A device required by electric-discharge light sources such as fluorescent or HID lamps to regulate voltage and current supplied to the lamp during start and throughout operation.

What are the two types of ballast used in fluorescent lighting?

There are two basic types of fluorescent ballasts: magnetic (low frequency) and electronic (high frequency). Most fluorescent ballasts are now electronic, which are more efficient than magnetic ballasts.


Electronic ballasts

An electronic ballast uses solid state electronic circuitry to provide the proper starting and operating electrical conditions to power discharge lamps. An electronic ballast can be smaller and lighter than a comparably rated magnetic one. An electronic ballast is usually quieter than a magnetic one, which produces a line-frequency hum by vibration of the core laminations.

Current limiting

An electrical ballast is a device that limits the current through an electrical load. These are most often used when a load (such as an arc discharge) has its terminal voltage decline when current through the load increases. If such a device were connected to a constant-voltage power supply, it would draw an increasing amount of current until it is destroyed or causes the power supply t…


For simple, low-powered loads such as a neon lamp, a fixed resistor is commonly used. Because the resistance of the ballast resistor is large it determines the current in the circuit, even in the face of negative resistance introduced by the neon lamp.
Ballast was also a component used in early model automobile engines that lowered the supply voltage to the ignition system after the engine had been started. Starting the engine requires a sig…

Reactive ballasts

An inductor, usually a choke, is very common in line-frequency ballasts to provide the proper starting and operating electrical condition to power a fluorescent lamp or HID lamp. (Because of the use of the inductor, such ballasts are usually called magnetic ballasts.) The inductor has two benefits:
1. Its reactance limits the power available to the lamp with only minimal power …

Fluorescent lamp ballasts

This technique uses a combination filament–cathode at each end of the lamp in conjunction with a mechanical or automatic (bi-metallic or electronic) switch that initially connect the filaments in series with the ballast to preheat them. When filaments are disconnected, an inductive pulse from the ballast starts the lamp. This system is described as "Preheat" in North America and "Switch Start" in the UK, and has no specific description in the rest of the world. This system is common …

ANSI ballast factor

For a lighting ballast, the ANSI ballast factor is used in North America to compare the light output (in lumens) of a lamp operated on a ballast compared to the lamp operating on an ANSI reference ballast. Reference ballast operates the lamp at its ANSI specified nominal power rating. The ballast factor of practical ballasts must be considered in lighting design; a low ballast factor may save energy, but will produce less light. With fluorescent lamps, ballast factor can vary from the …

Ballast triode

Early tube-based color TV sets used a ballast triode, such as the PD500, as a parallel shunt stabilizer for the cathode ray tube (CRT) acceleration voltage, to keep the CRT's deflection factor constant.

1.Videos of What Is In an Electronic ballast


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