[NJARC] Regarding LED pilot lamps.....

[Jim Whartenby]

High intensity white LEDs are cheap.  I picked up a hundred on eBay for under $7 (free shipping out of New York) to make up replacements for those fuse type lamps used in old stereo receivers.  Since the reverse voltage breakdown for LEDs is only about twice or so the forward voltage drop, I connected two white LEDs in anti-parallel and used a 160 ohm resistor for a 20 mA current limit with the available 6.3 vac supply.  This way you can directly connect the LEDs to AC without worrying about exceeding the LED reverse voltage breakdown rating.  In other words, the "off" LED only sees the forward voltage drop of the "on" LED.

I aimed the LEDs to reflect off of the back of the lamp compartment so that the light would diffuse well.  It looked quite nice when finished.  If you want something brighter then the 20000 mcd (20 candles) of these LEDs, just parallel more of the LED assemblies.  But believe me, 20 candles is pretty bright, probably brighter then the incandescent lamp you are replacing.
Jim


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 From: "kd4hsh at juno.com" <kd4hsh at juno.com>
To: njarc at mailman.qth.net 
Sent: Tuesday, June 18, 2013 1:03 PM
Subject: [NJARC] Regarding LED pilot lamps.....
 

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Regarding LED pilot lamps..... Take a peek at Cree's tower LED assembly in their new 60 W replacement. http://www.cree.com/lighting/products/indoor/lamps/60w-replacement-warm-white-type-a-led-bulb I have puchased one of the daylight versions and am really impressed by the light dispersion. I could see the same technique working for a pilot lamp replacement.  (four 1206 chip LEDs mounted on a stalk).  Should be far, far superior than just mounting a T- 1 3/4 white LED in the lamp socket. Robert
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