On Jun 18, 9:52*am, spamtrap1888 wrote:
On Jun 17, 5:33*pm, "Arfa Daily" wrote:





"mike" wrote in message

...

On 6/17/2012 4:32 PM, wrote:
I want to put an LED to test my phone line, which I found to be ca 50v.

Where/how do I find the right LED?

THe LEDs at Radio Shack are all like 2v (yea I remember VCC of 2.3 on
diodes
in my EE2 for non EEs course).

Should I just use a regular bulb, like the kind used for Christmas
lights,
instead? (what about the LEDs used for CHristmas lights? Shouldn't they
work?)

Besides, I really only want ONE LED.

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A series resistor will answer your question.
Assume you now all about what happens when you load a phone line.

And of course what happens when a ring signal appears across the line ....

Reminds me that back in the day, the radio studio phone had two lights
that flashed instead of a ringer. The lights looked like a salt and
pepper set. Maybe the OP could put a neon lamp across the phone line.- Hide quoted text -

- Show quoted text -

It depends on what he wants the leds to do, light up the room, or only
light up when the phone is ringing. 50 years ago I designed the telco
circuits that detected when a customers wanted service. It was a pain
to distinguish between a real off-hook from the customer and line
leakage due to poor cable insulation, squirrels, etc.