Simple Florescent Lamp Driver

From Electronics Wiki

Description

This is a simple fluorescent lamp driver. It can be used to drive a typical 14 watt bulb like the
screw in type you buy to put in your lamps for saving power. If you use that particular bulb you
must remove the circuit board first. Be very careful not to break the bulb. It would be much
easier to just buy a fluorescent bulb at a hardware or even grocery store. At any rate you can
attach the two unconnected wires from T1 (in schematic) to the fluorescent lamp of your choosing.
On the long tubular type you will attach one wire from T1 output to one end of lamp and the other
to the opposite end.

Part List

1. R1 about 220 ohms 1/4 watt

2. C1 should be at least a .2uF capacitor.

3. Motorola 2n3055 Power Transistor

4. R2 about 100 ohms at least one watt.

5. T1 use Amidon ferrite toroid core / no. 43 mix at least 1 inch diameter

• Note: Part numbers for Amidon go like this. A .8 inch core made of ferrite number 43 mix would read like this: FT-80-43 Try to get larger. One inch or more.

The windings on the transformer consist of 30 gauge enameled wire. The primary should be at least 20 turns. The secondary should be a good 800 turns. With an input of 6 volts DC, you will have about 2000 volts output at 14 watts.

The circuit is simply an Armstrong Oscillator with tickler coil feedback. That means you actually have two primaries both 15 to 20 turns only they will be wound out of phase with each other. That is because the transistor amplifier/oscillator is in common emitter configuration which means the collector output will be 180 degrees out of phase with the input. So in order for the feedback to add (positive feedback) the wires from the tickler must be reversed from the primary supply. The way to determine this is very simple. Hook the tickler up one way, and if it does not oscillate then reverse the leads.