The document discusses electronic ballasts for fluorescent lamps. It describes the different types of electronic ballasts including electromagnetic, hybrid, and electronic ballasts. It explains the basics of electronic ballasts using a half-bridge configuration and resonant circuit to strike the lamp. It also discusses starting methods for electronic ballasts including instant start, rapid start, and programmed start. Additionally, it provides details on fluorescent tube construction and operation, including the lamp structure, how the lamp works, and startup circuits. Finally, it lists the advantages of electronic ballasts such as being dimmable, energy saving, and having no flickering effect.

1. Electronic Ballast
Fundamentals
Submitted by
Balvant Singh
EC-A (final yr.)
0922231025

2. Contents
1. Types of Ballast
2. Basics of Electronic Ballast
3. Starting Methods
4. Fluorescent tube
5. Lamp Structure
6. Working of lamp
7. Startup Circuit
8. Advantages of EB

3. Types of Ballast
1. Electromagnetic
2. Hybrid
3. Electronics
 Purpose of EB
a. Provide a start−up voltage,
b. Maintain a constant current,
c. Assure that the circuit will remain stable.

4. Basics of Electronic Ballasts
C1
L
C2
 Halfbridge configuration
 The resonant circuit strikes on the lamp

5. A. Instant start electronic ballasts
Start lamps without
delay (<0.1 seconds) or
flicker by providing a
starting voltage that is
sufficiently high to start a
discharge through the
lamps without the need
for heating lamp
electrodes. , the starting
voltage is about 600V.
Lamps operated by
instant start ballasts
typically operate 10,000
to 15,000 switch cycles
before failure.

6. B. Rapid start electronic ballasts
Start lamps quickly (0.5
– 1.0 seconds) without
flicker by heating the
lamp electrodes and
simultaneously applying
a starting voltage.
Lamps operated by rapid
start ballasts typically
operate 15,000 to
20,000 switch cycles
before failure.

7. C. Programmed start electronic ballasts
Programmed start
ballasts are designed to
provide maximum lamp
life in frequent lamp
starting applications
such as in areas where
occupancy sensor
controls are used. .
Lamps operated by
programmed start
ballasts typically operate
up to 50,000 switch
cycles before failure.

8. Fluorescent tubes
 Much more efficient than incandescent
lamps : 2 to 4 times more efficient.
 Less energy required to operate.
 Eco-friendly for environment.
 The lamps are much cooler than
incandescent lamps.

9. Lamp Structure
 The lamp is a sealed tube
containing mercury vapor
and some inert gases
such as argon at very
high pressure
 The inside of the tube is
coated with phosphor
 At the ends of the tube
there are filaments or
electrodes

10. How does it work?
 When the tube is off it does
not conduct
 It is turned on by a high
voltage which excites the gas
inside the tube
 Once the tube conducts on a
lower voltage is sufficient to
maintain conduction
 The electric current passes
through the gas and emits
UV, the internal phosphor
coating converters the UV to
visible light
 The color of the light cab be
varied by different
combinations of phosphors

11. Lamp starting
 When the lamps is off the tube is non
-conductive
 The tube must be excited or started by a
high voltage
 After the lamps is started the lamp
voltage drops
 A current limiting “ballast” is needed in
between the power source and the lamp

12. Start up circuit

13. Starter switch

14. Advantages:
 1) Dimmable (only applicable for
expensive products that are not
commercially competitive in public
lighting systems);
 2) Energy saving;
 3) No flickering effect.