A dimmer for various lighting devices

Incompatibility of compact fluorescent lamps (CFLs) and light-emitting-diode (LED) bulbs with conventional light dimmers is a problem for consumers today. This thesis proposes a dimmer circuit that is suitable for incandescent bulbs, CFLs and LEDs. Different kinds of lighting devices are studied and tested with variable AC and DC sources. The proposed dimmer circuit is designed, simulated, built and tested with various lighting devices. Experiments are performed in order to observe the electrical characteristic of the dimmer and optical characteristic of the lighting devices when they are used with the dimmer circuit. The experimental results show that the proposed dimmer can be used with these kinds of lighting devices within special output voltage ranges. It is observed that incandescent bulbs, CFLs and LED bulbs have different voltage ranges for dimming operation and this creates need for specific output voltage ranges of the dimmer for each kind of lighting device. This can be achieved by using an application-specific PWM generator system that operates the power circuit of the dimmer within a specialized voltage range according to the lamp type.