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Picture of LED Dimmable Lightbox
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Build your own 18 watt LED light box to fight the winter blues. This lightbox is diffused and dimmable using PWM. If you have a lamp timer, you can use it as an alternative to an alarm clock.

Step 1: Materials

Picture of Materials
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Light Box
  • 6 x 3W white LED
  • Heatsink
  • Metal box
  • on-off switch
  • 2.1mm DC power jack
  • 12V 2A power supply
  • Cable ties
  • Epoxy putty
  • Twist ties
  • Plastic diffuser
  • Epoxy
  • Wires

Dan's PWM LED Driver
  • 1 x NE555 Timer
  • 2 x IRFZ44N N-channel MOSFETs
  • 2 x 2N3904 transistors
  • 1 x 0.01 uF ceramic capacitor
  • 2 x 0.1 uF ceramic capacitors
  • 1 x 50k potentiometer
  • 2 x 100k ohm resistors
  • 2 x 0.82 ohm 1 watt resistor
  • 4 x  1N4148 diodes
  • PCB
  • PCB standoffs
 
famosas1 year ago
hi. im new to electronic. i want to ask this. how about the maximum effiency of your driver? thanks
hanlin_y (author)  famosas1 year ago
Around 90% efficient in this circuit.
then if i use a higher voltage supply i use buck converter so the efficiency will decrease more right?
what is the rating for your adapter?
thanks
hanlin_y (author)  famosas1 year ago
You can add more LEDs so their forward voltages add up closer to the power supply's. I used a 2A 12V adapter.