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Author Topic: 555 Timer PWM led light  (Read 2574 times)

Offline SkyWatcher123

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555 Timer PWM led light
« on: January 01, 2019, 03:18:52 AM »
Hi all, was looking at Patrick Kelly's information about under driving led bulbs, so I decided to experiment.
I cut apart some standard 5.5 watt - 40 watt equivalent warm white led bulbs.
I cut the board into 2 led chip pieces, which has thick aluminum backing.
Each led chip is rated at 6.5 volts, meaning 2 leds are in series on 1 led chip, with 2 in series for a 13 volt max.
I made 2 of my own design bulbs, using cd/dvd disc for mounting, then superglued the led pieces in place, each piece is in parallel with 5 other led pieces.
Using 555 timer type circuit, with pin 7 as output, connected to TIP120 transistor base.
The light output is very good, for only 1.25 watts input or 11.92 volts at .105 amps,

with 2 led units so far, as I plan to make more to add in parallel.
Using 12 volt computer power supply.
Comments or questions welcome.
peace love light
Also, I detect no heat from these homemade led bulbs, even when a single unit is powered with 2 watts input, so the efficiency seems high.

Offline SkyWatcher123

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Re: 555 Timer PWM led light
« Reply #1 on: January 01, 2019, 08:22:14 AM »
Hi all, here is the circuit I used.

peace love light