The occasion for this project was retrofitting an illuminated wall picture with LED backlighting. As soon as I applied LED power, the brightness blinded me — much brighter than the original T20 ...

Seen in the accompanying schematic, the 555 square wave generator drives an MPF102 FET, which in turn drives a D718 power transistor that provides a “pulsed” 12V variable duty cycle driving the LED ...

See Fig. 1, the dimmer schematic. The 555 Timer IC does produce a fairly square wave output, so filtering is important. However, the 6.8K resistor that is in a series with the 555’s output to the ...

One of the biggest challenges for new, energy-efficient CFL and LED-based lights that will replace incandescents is working with existing triac-based dimmer switches. Triac dimmers vary widely in both ...