It is centered around the theory of oscillating on the primary of a transformer to accomplish a secondary high voltage able to ionizing the gas protected inside the tube and thus enable it to be illuminated
Inside the circuit each of the resistors are 1W and 12W rated. The transistor has to be effectively heatsinked.
As demonstrated, it has an oscillator circuit which appears that it would not work. However just look a little bit in depth towards the configuration of L1 / T1.
Over a ferrite rod coil the two transformer winding (L1) are attached in the form of the inductor of transistor (T1). Therefore we have the oscillator circuit in the feedback mode. For every single cycle of a percentage of power transistor it is recognized by the winding L1 which retriggers the transistor and consistently runs the system. However , exactly how this inductor is created? Let's learn it
First we have to get a ferrite rod for example which are found in AM radios 6cm long.
Cover this bar with 60 turns of enameled wire 1 mm thick. This becomes the primary winding, which will be connected with the power transistor. Once this primary winding is completed fix it firmly in place by wrapping a layer of transparent insulation tape, and if possible secure the wire ends with fast curing epoxy glue or quick fix glue
After this wind the secondary winding on the center with 13 turns of 0.4mm enameled wire turns which will form the feedback winding or feedback loop L1. This winding will ensure that the initiates oscillating as soon as powered. As before secure this winding also with a layer of insulation tape and epoxy glue.
Finally now wind 450 turns of 0.4mm enameled wire forming the secondary side of T1. This winding is completed in three layers of 150 turns each, to create a decent layered winding and not a heaped bulk of wires. Make sure that between each layer a layer of insulation tape is wrapped to keep the layers intact and firmly wound. Done!...your inductor L1 for the 40 watt fluorescent emergency lamp circuit is complete
Before you turn this circuit ON, make sure the inductor is in the correct phase. This check this initially connect the fluorescent tube to the secondary and momentarily switch ON the system. If the tube does not light at all would indicate a incorrect phased primary side of (L1). Now simply swap the primary side wires with the transistor. Now check it again and this time you will find the tube illuminating brightly. But If the tube turns on at the first attempt (before reversing the wires, you need not do any mods!).
Next adjust the position of the coil L1 to the most optimal position over the ferrite and once done we could remove the limiting resistance (the 2.2 ohms) and allow the system to be powered directly.