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can leds be connected to a phone/phone line? Answered


i have an old red baker lite phone and would like to put some leds inside so that when the phone rings it lights up (like the bat phone) could this be worked of the voltage of the phone line or would a relay have to be involved with batteries
i`v not take the phone apart yet to so have a look if any 1 has done some thing similar

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Avadhut.DeshmukhBest Answer (author)2011-07-01

You'll need to buy a phone extension cable. I got mine for £1. Then strip the wires. Black and Yellow carry the power, so connect those to your bridge rectifier, and you're set. 48V is good for 12 LEDS, which use about 3.8V each. The larger the resistor, the less light you'll get from your LEDs. But if your resistor is too small, the phone won't work. So you'll need to strike a balance. A 1k resistor worked for me. The phone sounds odd, but it still works.

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user

This is illegal in most parts of the world by the way.....In the UK, people have been convicted of stealing electricity by this method..

Steve

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user

Oh my God !!!  Stealing electricity how much you know about India !!! working not police !!! what !!!

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rickharris (author)2011-07-01

IN the UK it is illegal to tamper with the phone lines or connect anything that isn't approved.

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orksecurity (author)rickharris2011-07-06

I'm not sure whether unapproved devices are technically illegal in the US, but telco would be within their rights to cancel your account and yank the connection to your house. And don't think they aren't aware of how much power is being drawn, or that it would be hard for them to determine where it's going.

This is necessary to protect the the phone company, and your neighbors, from your mistakes.

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steveastrouk (author)2011-07-01

It can be done, but phone companies are very leery of people doing it - the system isn't really designed as a power source !! There's a high voltage available when it rings.

Steve

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andybuda (author)steveastrouk2011-07-03

iv not tested the phone line with a volt meter yet do you know what sort of power i would be looking at when the phone is just connected and when the thing rings. the thing is im only taping off the phone line to be used as a trigger but if the voltage is good enough to simplify the circuit im all for that
thanks for replying

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