The transformer you have should be OK. Just use the rectifier bridge to drive the LEDs only. Put a filter capacitor on the output of the rectifier bridge (watch for polarity). A few hundred uF should be enough since we're only dealing with a current of about 20 mA. You only need a one-amp rectifier bridge (those are about the size of an 8-pin DIP package). In fact, even an IN4001 diode should be OK if you have a filter cap of around 470 uF or more (make sure to use one rated for 25VDC or better). You should have about 15VDC across the capacitor so a 470 ohm resistor will give you a current of roughly 18 mA if you connect the two LEDs in series. The low-voltage alcove light remains connected straight to the AC output of the transformer.
80,000hrs. MY ***!
- Thread starter deano
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The_LED_Museum
*Retired*
Re: 80,000hrs. MY TOLIET MUSCLE!
The heirarchy concurs!!! /ubbthreads/images/graemlins/grin.gif
The AC from the transformer is what's killing the LEDs.
Use a bridge rectifier to change that to pulsating DC, and place a good size (1000µF or more) electrolytic capacitor (they're polarity sensitive too, be sure you have + and - on there right) across the DC output to help smooth out those pulsations; this should greatly reduce or even elimate flicker.
The heirarchy concurs!!! /ubbthreads/images/graemlins/grin.gif
The AC from the transformer is what's killing the LEDs.
Use a bridge rectifier to change that to pulsating DC, and place a good size (1000µF or more) electrolytic capacitor (they're polarity sensitive too, be sure you have + and - on there right) across the DC output to help smooth out those pulsations; this should greatly reduce or even elimate flicker.
B@rt
Flashaholic
14C
Enlightened
Buy a "wall wart". Plug-in DC power supplies come in a variety of voltages and current capabilities...relatively cheap. Hell I might even have one I could send you in the old junk box if you figure out what voltage and current you want.
btw i have an early nichia white that i installed in a 12v fluorescent desklamp as a nightlight.i converted this fixture in 97 and it has been on ever since.
only goes off when the main light is on as it is across the switch.running 15-20 ma and still looks as good as the day i installed it.i swapped it with another from the same batch and saw no difference.estimate over 50k hours on it.
only goes off when the main light is on as it is across the switch.running 15-20 ma and still looks as good as the day i installed it.i swapped it with another from the same batch and saw no difference.estimate over 50k hours on it.
