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I need to turn on an electric ballast without connecting the fluorescent tube, since I'll use the ballast's output to power another device.

My single-lamp ballast has 4 output wires. This is how they are supposed to be connected to the light tube:

enter image description here

If I plug in the ballast without nothing connected to it, I get no voltage between pins 21 and 24 (the ballast doesn't turn on). I discovered that this is because the ballast needs to "sense" the filaments of the lamp in order to turn on. So I tried adding two plastic film capacitors between pins 21-22 and between 23-24, and now the ballast turns on when I plug it in, but it shuts off after about 3 seconds.

I thought about replacing the capacitors with high-wattage resistors in order to simulate the filaments and keep the ballast turned on. Would this work? Do you have any better idea? Thanks.

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  • \$\begingroup\$ AC or DC voltage - what did you use? \$\endgroup\$
    – Andy aka
    Commented May 3, 2015 at 14:27
  • \$\begingroup\$ @Andyaka Mains AC voltage - 230 VAC. \$\endgroup\$
    – user2747949
    Commented May 3, 2015 at 15:00

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Electric ballast for tube light (TL) is a constant current source and treats filament as the load.. so connect a WW resi. equivalent to TL filament in both 21-22 and 23-24 terminals separately and try. be careful about the voltage between 21 & 23. VTIngole

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