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Circuits designed by David
Johnson, P.E.
Last Updated on:
Saturday, December 23, 2017 03:21 PM
List of Dave's Circuit Designs
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More
LED's; White LED's;
Control;
Lamp Control
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1W White LED
Night Light
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| As many
of you know, I have a pet peeve with poorly made LED night lights. Often, the
light from the LED quickly fades, so within months, the light is useless. I have
posted several versions of modified night lights using higher quality components.
This circuit is yet another version, which produces much more light than those other
designs. The circuit brings together two high power white LEDs made by Cree with a
compact AC to DC power supply from Bias Power. |
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This simple circuit uses a one watt power supply module from Bias Power,
model BPS1-08-00. The tiny module can crank out about 8 volts DC, fully isolated form the
AC power line, whose voltage can range from 85vac to 250vac. The DC output of the
module is fed to two one watt white LEDs, from Cree, wired in series. A 13 ohm ½
watt resistor in series limits the LED current to about 125ma. Although the LEDs are
rated at one full watt, the circuit routes only one half watt into each part. The
result is more than enough light for a night light and it should allow the light to last
for many years. |
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I suggest mounting the two LEDs onto an aluminum bar or plate, to act as a
heat sink. Excessive heat will shorten the life of the LED. You can remove the
guts of a suitable night light and replace the internal parts with this circuit. |
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You can buy the Bias Power module at the address shown below. The
Cree LEDs can be purchased from eBay. Other one watt LEDs may also work but may not
last as long. |
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Nu-Way Electronics, Inc. (info@nuway.net)
165 Martin Lane
Elk Grove Village, IL 60007
800-323-7957 |
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Click
on Drawing Below to view PDF version of Schematic |
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