The project “12V DC Ballast” using power transistor 2N3055 is used to glow AC tube light using DC source. The circuit of DC ballast is basically a DC to AC converter. DC ballast of various capacity (in watts) is already available in markets. The circuit posted here is of 20W capacity i.e. (it can drive load up to 20 watts).
Circuit Description of 12V DC Ballast
The circuit of 12V DC Ballast uses very few components and is very simple to understand shown in figure 1. As we have already stated that the circuit posted here can glow 20W tube light efficiently.
When power supply is given to the circuit base bias voltage is generated at base of transistor T1 through resistor R1 and inductor L2. Similarly, collector bias voltage is generated through inductor L1. When transistor is on capacitor C2 with inductor L2 forms tuned circuit. At the same time L1 get energized as a result electromagnetic energy is generated.
When base voltage starts to increase the biasing voltage irregulates as a result transistor goes in off mode. When transistor T1 became off inductor L2 start to deenergized as a result back EMF produce on all three inductors L1, L2 and L3. This back EMF again turned on the transistor T1.
This process of fast switching (ON and OFF) of transistor, AC voltage is generated. The generated AC voltage is now stepped up in order to glow Tube Light.
PARTS LIST OF 12V DC BALAST
|Resistors (all ¼-watt, ± 5% Carbon)|
|R1 = 2.7 KΩ
R2 = 1Ω, 2 Watts
|C1 = 100 µF/16V (Electrolytic Capacitor)
C2 = 0.01 µF (Ceramic Disc)
|T1 = 2N3055
D1 = 1N4001
|L1 = 16 turn 22 SWG
L2 = 14 turn 33 SWG
L3 = 250 turn 33 SWG
Core = 7 cm Ferrite Core