Tuesday, 9 April 2013

Lighting fluorescent bulb using 9V battery.

Dear everyone I am back!

Lately I ve been testing this circuit. Its called 'Joule thief' and I tried using it to power up a fluorescent bulb using just 9V battery.

Here is the schematic I ve been using:

Or if the above photo is not too clear...

I have used flyback transformer salvaged from old CRT television. The primary coil is centre-tapped with 8 turns for each coil. 2N3055 is used as switch due to its high power rating.

Choke 34uH) and electrolytic capacitor (100uF) are used to provide constant current and voltage to the primary coils.

Output voltage from the secondary winding of the transformer is capable of driving small fluorescent bulb.

The photos explain my project more:

My setup. Battery at the lower part, the circuit, flyback transformer (bulky black chunk) and the farthest stuff, the fluorescent bulb.

I have removed the circuit board below the bulb and just taking the bulb. I connected a wire to each of the terminal. Each is then connected to each terminal of the flyback transformer's secondary.

The video. 

 The bulb appears quite bright in the dark for 9V supply.

I tried adding a capacitor (1uF, or you may try any value) across or in parallel to the 500 ohm resistor and guess what, it made the bulb shines brighter! This time I ve changed the bulb to a longer one to spread the lights wider but I think this capacitor effect also works for the smaller bulb.

The longer fluorescent bulb

As usual I removed the adds on from the bottom (which comprises of a capacitor and a fuse-like stuff) and connect the bulb's terminals directly to the output of the flyback transformer.

 Before lighting up.

Before adding capacitor.

 After adding a capacitor.

Thanks for reading.

Update (11 Apr 2013): I tried using my homemade flyback transformer and the circuit works, with an additional capacitor  (around 0.1uF) attached between each end of the primary winding. Here is the photo:

The flyback transformer (homemade) that I have used:
The vertical ferrite rods are longer this time compare to the previous ones cuz those shorter ones are being used for other projects.

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