need help for cfl lighting

[pier1]

i need help to make a circuit which consumes very less current for lighting up a cfl tube (9watts) with starter from a 6 volt battery . please help me .

 

[audioguru2]

9W for the light tube and maybe as much as 1.8W for the voltage stepup circuit is a total power of 10.8W.
Therefore the current from a 6V battery is 10.8W/6V= 1.8A. Do you have a huge battery to supply a current so high?

 

[pier1]

i saw a circuit that has few components and has a 9 watts cfl tube, but the whole circuit pulls only 700mA from a 6volt 4Ah battery . That is why i asked for it . please do help me .

 

[audioguru2]

700mA from a 6V battery is only 4.2W. The inverter is about 80% efficient so the 9W bulb gets only 3.36W. That would be quite dim. Is that what you want?

 

[pier1]

that is not a bulb . it is a compact flurocent lamp(tube) with a built in starter . while it starts the lamp flickers about 2 to 3 seconds then goes to steady state

 

[audioguru2]

A compact fluorescent light needs a ballast to make it work. A very old ballast was a big coil of wire as an inductor, then it had a starter with mechanical contacts or a small neon bulb.
Modern ballasts are an electronic circuit with a power oscillator driving a high frequency small stepup transformer and a high voltage current limiter.

Our projects section has two projects that light small fluorescent tubes. The 1st project uses a 6V or 8V battery and its bulb is about 9W but doesn't say. It uses a transformer but the project doesn't show it or say any spec's about it.
The 2nd project is similar but needs a 12V battery.

http://www.electronics-lab.com/projects/motor_light/002/index.html
http://www.electronics-lab.com/projects/motor_light/027/index.html

 

[pier1]

no that dosnt work out . i really need it from a 6 volt battery that draws less current . please try to help me cause i am badly in need of it .

 

[audioguru2]

The only way to reduce the battery current is to reduce the circuit's power output. That makes the light tube less bright.

 

[pier1]

but will that effect the brightness of the tube ?

 

[audioguru2]

but will that effect the brightness of the tube ?

Of course. It takes power to make light. Less current from the battery is less power so is less the amount of light.

 

[pier1]

but the circuit i saw was bright enough and draws only 700 mA from the 6 volt battery . I think BPL has started one without starter in the tube . how does that work then ?

Ive attached an image of the tube . u can have a look at it .

View attachment 39811

 

[audioguru2]

I have lots of newer compact fluorescent bulbs in my home. The tube is a spiral. Most use 15W and a few use 23W.

The electronic ballast which is part of my bulbs pre-heats the filaments at the ends of the tube for a moment then gives it a high voltage spike to start it without flickering.

The ballast has a rectifier and filter for the mains then a 40kHz stepup inverter. A current-limiting capacitor feeds the tube.

"700mA from a 6V battery is only 4.2W. The inverter is about 80% efficient so the 9W bulb gets only 3.36W. That would be quite dim."

 

[pier1]

this is the ckt i told u , i saw .

View attachment 39817

 

[pier1]

i'm sorry for that space

 

[audioguru2]

It is a huge paper with a tiny schematic on it.
Make it, measure its current and see how dim or bright it is.
Are you going to take it camping? The bears might eat it. ;D

 

[pier1]

i already measured its current . as i said earlier it draws only 700 mA from a 6 volt battery . and the brightness is very good and sufficient . but i dont know the transformer details . thats the problem . i know all the other values .

 

[audioguru2]

I have never seen a transformer with an extra winding like that. It must be custom-made for the light.

 

[pier1]

since it self oscillating it must be the one for oscillating , some say that it is a feedback winding .

 

[audioguru2]

since it self oscillating it must be the one for oscillating , some say that it is a feedback winding .

It is a feedback winding. Your schematic shows it shorted, and a resistor is missing for one of the transistors.