Inverter Circuit for 40W Fluorescent Lamp

Inverter circuit for 40W fluorescent lamp

This is the schematic diagram of inverter circuit for 40W fluorescent light, this is great circuit for emergency lamp. This inverter allows you to power up 40W fluorescent tubes from any 12V source capable of delivering 3A. The circuit is very simple, inexpensive and easy to build. Please use safety equipment since this circuit work with high voltage electricity.

Parts List:
R1 = 180 Ohm 1W
R2 = 47 Ohm 1/4W
R3 = 2.2 Ohm 1W Resistor (only needed once)
C1, C2 = 100uF/16V
C3 = 100nF
Q1 = TIP 3055 or 2N3055 or equivalent
MISC = Wire, Case, Board, Heatsink For Q1, heatshrink, AM antenna rod for coil

Inverter, is an electronic device or circuitry that changes direct current (DC) to alternating current (AC). The input voltage, output voltage and frequency, and overall power handling depend on the design of the specific device or circuitry. The inverter does not produce any power; the power is provided by the DC source.

L1/T1 Winding Procedure:

You will need an AM antenna rod that is about 60mm (2.5 inches) long to wind T1/L1 on. T1/L1 are wound on the same core. Shrink a layer of heatshrink over the core to insulate it. Leave 50mm of wire at each end of the coils.
Winding for Inverter circuit for 40W fluorescent lamp

  • Primary: Wind 60 turns of 1mm diameter enamelled copper wire on the first layer and put a layer of heatshrink over it.
  • Feedback: Wind 13 turns of 0.4mm enamelled copper wire on the core and then heatshrink over that.
  • Secondary: This coil has 450 turns of 0.4mm enamelled copper wire in three layers. Wind one layer and then heatshrink over it. Do the same for the next two.

How to calibrate/test the circuit:
Connect the 2.2 Ohm 1W resistor (R3) in series with the positive supply from the battery. Hook up a 40W fluorescent tube to the high voltage ends of the transformer. Momentarily connect power (power up the circuit). In the case the tube doesn’t light up immediately, then reverse the connections of L1. If the tube still doesn’t light up, check all wiring connections. When you get the tube to light, remove the 2.2 ohm resistor and the circuit is ready for use. You will not need R3 again.

This circuit is should be used for 220V fluorescent lamps. It will work with 120V units just fine, but will shorten the life of the fluorescent tube.

Source: 40W Fluorescent Lamp Inverter Diagram

2 thoughts on “Inverter Circuit for 40W Fluorescent Lamp

  1. 3A@12V is 36W. Given the efficiency of a simple single ended converter like this is low, the lamp brightness will be less than a 40W tube run from the mains.
    Also, absence of filament windings to preheat the tube will cause cathode stripping and short lamp life.
    There is no such thing as a “220V fluorescent lamp” or any other voltage. The voltage drop across a fluorescent tube is dependent on the mercury vapour being ionised. The control gear is what determines the supply voltage, not the tube.
    Just FYI, a 40W tube drops about 108V.
    Incidentally, this circuit has been taken from an Australian magazine, “Talking Electronics”.

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