What does a Ballast do ?

Basiccaly just wondering what a ballast actually does ???

A ballast controls the electricity flowing (current) into the bulb. HID and flourecent lights are so effective at producing light that, without something to regulate the electricity flowing into the bulb, the light will continue to gain intensity until the bulb stops working. That's where a ballast comes in. It supplies the initial electricity that creates the light, and then it regulates the amount of electricity flowing through the bulb so that the right amount of light is emitted.

Im an apprentice electrician and i basically stole this out of my book.

aha well my dads a electrician, and he said he may beable to make a ballast that is cheaper then buying one ?? is it possible to make your own ??

Yes you can buy all the parts to build your own

Ballasts are basically 3 parts - Power supply, capacitor and igniter. Match up the right parts and you are golden. I have a lighting place near me that will tell you which parts need replacing when there is a failure. The power supply rarely goes bad. The last time I rebuilt my 400 watt HPS it costed less than $50.00 to replace the capacitor and igniter. Thanks to Rezin for a great explanation of what the ballasts do. + rep to Rezin.

unless your old man knows exactly what to do i wouldnt risk it. ballasts are 1 part of lighting u dont wanna mess with , they have the capabality to get insanely hot and any mistakes could cost you your life or your house/grow room.

the 100watt cfls have a build in ballast u can see the big arse thing below the globe, thats it. id just go buy a hps kit there not that expensive.

Ballasts are not that complicated, especially for an electrician. We tear them apart and rebuild them around our shop all the time. Mind the capacitor though, it can hold a charge after the system is shut down.