fluorescent lamp project

Compact Fluorescent Lamps [CFL] are low in price, plentiful and easy to find. Unfortunately, the current crop of these lamps seldom lasts as long as their warranty. Usually only the electronics fail and the lamp part of the bulb assembly are still very useable to provide the necessary part for this project. So next time one of those new technology

bulbs refused to function convert it to a battery powered camping lamp. Using a saw cut the defunct light bulb apart along the sonic weld area, indicated by the red line in Figure 1. The object of the cutting is to separate and remove the fluorescent lamp from the rest of the circuit. The electronic circuit is usually on a small round printed circuit board that is loaded with surface mount components. It is possible to diagnose the cause of the failure and repair the lamp. To do this another identical bulb and sufficient patience is a requirement but unless it is a learning project, it is more trouble than what it is worth. After the cut is completed, mount the lamp with a few 4-40 screws, using the plastic ring on the metal side of an empty coffee can or some other suitable box. The newly built driver circuit, battery and maybe the battery charger can be housed inside that container. The battery for this project can be some rechargeable type. NiCd (Nickel Cadmium), NiMHd (Nickel Metal Hydride), Li-Ion (Lithium Ion) or sealed lead acid batteries will work properly, only their charger circuit differs. The driver circuit used here is a single transistor, blocking oscillator - Figure 2. Blocking oscillators are nearly ideal to drive fluorescent load because the phosphor glows a relatively long time after each excitation pulse. The higher the frequency - within reason - the brighter the bulb and the higher the circuit...

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