I have a Telechron clock radio from the early 1950's. I'm going to
build this circuit (it's in the middle of the page):
http://ourworld.compuserve.com/homepage ... page10.htm "AC
line-powered LED's"
My intentions are to have two soft blue LED's behind the clock dial so
I can see the clock at night. My question is this: Can I use an on/off
switch with this circuit? The switch I have is just a simple 2-
terminal interupter. Would it destroy my LED's having one line
connected while the other is switched off?
Bryan

On Sat, 25 Aug 2007 12:18:05 -0700, Totalrod2 wrote:

> I have a Telechron clock radio from the early 1950's. I'm going to
> build this circuit (it's in the middle of the page):
> http://ourworld.compuserve.com/homepage ... page10.htm "AC
> line-powered LED's"
> My intentions are to have two soft blue LED's behind the clock dial so
> I can see the clock at night. My question is this: Can I use an on/off
> switch with this circuit? The switch I have is just a simple 2-
> terminal interupter. Would it destroy my LED's having one line
> connected while the other is switched off?

No problem. At 60 Hz, an open circuit is an open circuit. Do you even need
the switch? LEDs are pretty reliable. The last Telechron clock I had had
a neon dial lamp with no switch.

On Aug 25, 2:18 pm, Totalr...@aol.com wrote:
> I have a Telechron clock radio from the early 1950's. I'm going to
> build this circuit (it's in the middle of the page):http://ourworld.compuserve.com/homepages/Bill_Bowden/page10.htm"AC
> line-powered LED's"
> My intentions are to have two soft blue LED's behind the clock dial so
> I can see the clock at night. My question is this: Can I use an on/off
> switch with this circuit? The switch I have is just a simple 2-
> terminal interupter. Would it destroy my LED's having one line
> connected while the other is switched off?
> Bryan

Hi, Bryan. Sure, it will work fine with only one side of the line
switched. As Mr. Rush says, an open circuit is an open circuit.

A couple of caveats, though. Many caps fail shorted in the event of
overvoltage. You should use a line voltage rated, "self-healing" cap,
which burns the section of the cap open where a surge or spike punches
through. This will prevent the rest of the circuit from smoking.

You should also be aware that the surface of LEDs are not necessarily
made to withstand line voltage. To be safe, put a lens or something
else over the top of the LED to keep the user from touching it when
powered, and also do not mount the LED directly in a metal chassis --
use a grommet or other method that will keep leakage current or
arcover from the body of the LED to the chassis.

Good luck, and think safety whenever working with line voltage.

Cheers
Chris