Low power, low efficiency - but simple way to drive LEDs from 127v

Other Types of Lights LED Light Bulbs
1

THIS INFORMATION IS PROVIDED WITHOUT ANY WARRANTY OF ACCURACY.

Ok. Idle hands once again....

The short version: The (huge) link below will take you to a voltage divider simulator. It should be a simple way to drive LEDs from a 110v outlet.

http://www.falstad.com/circuit/#%24+13+5.0E-6+7.619785657297057+50+5.0+50 v+192+352+192+112+0+1+60.0+180.0+0.0+0.0+0.5 d+192+112+320+112+1+0.805904783 w+320+112+352+112+0 174+352+112+352+336+0+48000.0+0.0050+Resistance w+368+224+464+224+0 162+464+224+464+256+1+2.1024259+1.0+0.0+0.0 162+464+256+464+288+1+2.1024259+1.0+0.0+0.0 162+464+288+464+320+1+2.1024259+1.0+0.0+0.0 162+464+320+464+352+1+2.1024259+1.0+0.0+0.0 r+464+352+352+336+0+2000.0 w+352+112+416+96+0 d+192+352+352+112+1+0.805904783 d+352+336+192+352+1+0.805904783 d+352+336+192+112+1+0.805904783 o+5+64+1+35+0.625+9.765625E-5+0+-1 o+9+64+1+35+40.0+9.765625E-5+1+-1 o+0+64+0+34+320.0+0.05+2+-1

The long version:

I have, for a long time, wanted a very weak light source, dimmable to almost nothing. An idle day and I decided to refresh my very old knowledge about circuits.The link above is the result so far.

This circuit has not been assembled and may be wrong so be careful. If anyone can point mistakes from the simulation, thanks in advance.

The led drivers available at DX, KD and company are designed to be powerful and efficient, this one is designed to be simple and dimmable. Hence, efficiency is low - if you take a careful look you will realize that there is a lot more power going to the resistor than to the LEDs - but it should be very easy to build. And I expect it to provide a nice, noise free (no voltage converter) low power night light, blinking at 120Hz if you have a 127V/60Hz outlet...

Thanks for reading and feel free to improve and modify!

2

Ok. The blinking was bothering me. A simple capacitor is added, and although the light output varies, it the LEDs no longer blink.

The new version is here:

http://www.falstad.com/circuit/#%24+13+5.0E-6+35.60246606707791+50+5.0+50 v+128+320+128+80+0+1+60.0+180.0+0.0+0.0+0.5 d+128+80+256+80+1+0.805904783 w+256+80+288+80+0 174+288+80+288+304+0+48000.0+0.5099+Resistance w+304+192+400+192+0 162+400+192+400+224+1+2.1024259+1.0+0.0+0.0 162+400+224+400+256+1+2.1024259+1.0+0.0+0.0 162+400+256+400+288+1+2.1024259+1.0+0.0+0.0 162+400+288+400+320+1+2.1024259+1.0+0.0+0.0 r+400+320+288+304+0+2000.0 w+288+80+352+64+0 d+128+320+288+80+1+0.805904783 d+288+304+128+320+1+0.805904783 d+288+304+128+80+1+0.805904783 w+400+192+544+192+0 c+544+192+416+400+0+1.0E-5+13.57691296637974 w+288+304+416+400+0 o+5+64+1+35+0.009765625+9.765625E-5+0+-1 o+9+64+1+35+0.0390625+9.765625E-5+1+-1 o+0+64+0+34+320.0+0.00625+2+-1 o+15+64+0+33+10.0+0.025+3+-1

TIP: In the java applet window, there will be a resistance bar (lowest bar at the right). This controls the trimpot and the power to the circuit.

3

Thats interesting. I simply use power adapters "wall warts" from name brand manufacturers to power my LED's from the wall socket. It lessens the chances of having one burn my house down or getting electrocuted and killed. Used electronics stores usually have several hundred to rummage through to find one that fits your needs. For dimming, I use a rheostat inline with the LED.

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How I wish I had something like that.....

The closer I can get here are old cell phone chargers. They will definitely reduce chance of burning the house down, but they are still expensive and less efficient than my simulation at very low power...