Introduction: FREE Hidden Electricity!

Picture of FREE Hidden Electricity!
This Instructable will show you how to tap into a FREE source of electricity! All you need is a phone line! All phone lines have a constant flow of voltage, around 40-70 volts (up to 100 volts when it rings!), but you can't just plug stuff into it and expect it to work. You can really mess with your phone system by doing that. I discovered how to do it the right way!

Step 1: What You Need...

Picture of What You Need...

1. Small project enclosure
2. (1) 240ohm resistor
3. (1) 510ohm resistor
4. (1) LM317L Regulator
5. (1) KBP210 Bridge Rectifier
6. (2) Phone line cables

Step 2: The Schematic...

Picture of The Schematic...

I connected the Positive end to one line of the female phone jack and the negative to the other. You could wire it directly to your light but I chose to do it this way so I could test other sources with just a phone jack interface cable. The Red and Green go to corresponding colors on the phone line that plugs into the wall.

Step 3: Final Steps...

Picture of Final Steps...

Mount the circuit in the project box and run your wires through two small drilled holes. Be sure to tie knots in the wires inside the box to prevent them from pulling out.

Step 4: Interface Cable...

Picture of Interface Cable...

I made an interface cable from an old wall adapter and phone line to connect the light to the box.

Step 5: Test It Out!

Picture of Test It Out!

After wiring the LED's in parallel, I plugged everything in and it worked great! It even powered off when the phone was picked up and flashed when it rang. While this won't power your new 60" HD Plasma TV, it will power small amperage electronics and could come in handy if the power goes out! Enjoy your FREE source of power.


TonyaA7 (author)2017-05-25

Hello, Like the work you've done. But i would like to know how you wired up the working components after you realized the is no need for bridge retifier. Just wonder if you could post a skematic like you have done with the corrections you mentioned.

Thank yo.


arc86 (author)2011-12-31

If you do this don't be surprised if the phone company finds out about it. But I want to offer a couple corrections.

First, don't use the KBP210 Bridge Rectifier. That's used to convert AC to DC but the voltage on the phone line is already DC so all it does is waste 1.4V of your power source (when current has to flow through diodes it burns up extra power). You can tell he has his multimeter set on DC voltage in the video, this verifies that's what's coming out of his wall jack. I guess it would save you if you accidentally connected the green and red wires backwards but just don't do that.

Second, if you already have DC, figure out what voltage you need for your device and use the LM317L or another adjustable regulator. He has the resistor network connected incorrectly so refer to the datasheet from Texas Instruments. What you need to do is hook up the resistors so when you get your desired voltage on the Output pin, the Adj pin sees 1.25V. The way he shows it hooked up it looks like the circuit will just output 1.25V (the Adj pin draws so little current it's at effectively the same voltage as the output it's hooked to through a resistor). You need one resistor going from the output to the Adj pin, and one going from the Adj pin to your ground.

Anyways, check your output with your multimeter before you hook it up to your valuable electronics.

usbg3rd (author)arc862012-02-02

i found out that the phone line contains 50-60V dc and a 110Vrms sine superimposed on it so u will need a rectifier ic too .....

i wonder why he isn't using filter capacitor? ???

by the way nice hacking :)

iTixle (author)usbg3rd2012-08-18

It makes no sense to me that the voltage would be DC. You can't transmit DC over very long distances.

SolidRaven (author)iTixle2013-07-07

That's a very large misconception. In fact you'll find that for high power long distance transmissions DC is far more cost effective.

Kiteman (author)SolidRaven2014-05-24

Actually, for anything over more than a few metres, DC power transmission has massive losses. High voltage + low current = much less resistance.

One if the main reasons cities went with AC was that DC system designs needed a power station almost every other block. Modern high-rise structures would need piwer stations part-way up the building.

nehmo (author)Kiteman2016-01-19

AC can be sent through a transformer, which will trade volts for amps. That's why power transmission is accomplished with AC. Your goal is to transmit power, that is, watts. (W=VxA) But the more amps you carry, the larger the wire you need.

You can distribute power using high voltage (and low amps) requiring a smaller cross-section area wire for the same wattage. Then, near the point of use, the AC can be sent through a step-down transformer converting the power to low voltage (and high amps).


Transmit 1,000V at 1A. This is 1,000 watts.

1A requires a small wire.

Near the point of use, convert the 1,000 watts with a transformer to 100V at 10A. This is still 1,000 watts.

The wire near the point of use is a bigger one (one capable of carrying 10A), but it is only used for a short distance.

(In reality there are line loses, but I ignored them for illustration.)

Kiteman (author)nehmo2016-01-19

The amusing thing is, I'm currently teaching this to one of my physics classes...

alexteh (author)Kiteman2016-10-11

kiteman, it is not amusing as you are teaching the wrong stuff to the physics class.

Kiteman (author)alexteh2016-10-11

Umm... I don't.

That's why my classes tend to come out at the top in exams...

wobbler (author)Kiteman2016-01-19

It's not that DC or AC have any differences in loss. You said it with the voltage comment. DC at a high voltage loses just the same as AC at high voltages. The loss is due to the amperage, higher voltages mean lower amperages for the same power and the lower current means less loss in the wires (power loss=I squared x R).

The real reason, as stated elsewhere, that AC is used is because it was cheap and easy to convert to higher voltages using AC with a transformer than any other method available in the past for DC. Large AC alternators/generators are also easier to build than DC dynamos which need complex commutators to maintain the DC output.

Kiteman (author)wobbler2016-01-19

You'll note I said "high voltage and low current".

wobbler (author)Kiteman2016-01-22

It wasn't the "high voltage and low current" that was the issue, it was the erroneous comments about DC transmission as follows:

"Actually, for anything over more than a few
metres, DC power transmission has massive losses." I repeat, the losses for AC and DC in terms of resistance losses down the wire are the same for either at the same voltage and current. High Voltage DC (HVDC) is in use already all over the world. The longest HVDC system currently (no pun intended!) is is the Rio Madeira link in Brazil which consists of two bipoles of ±600 kV, 3150 MW each, connecting Porto Velho in the to the Sao Paulo area. The length of the DC line is 2,375 km (1,476 mi), which is slightly more than a few metres. (quoted from Wiki)

"One if the main reasons cities
went with AC was that DC system designs needed a power station almost
every other block. Modern high-rise structures would need power stations
part-way up the building." This is totally wrong. DC does not in any way need a power station almost every block (see the above reference to obviously disprove that) although historically it may have been the case. Modern high rise structures similarly would not need a power station part way up the building. Like most distributed electrical systems across any location, it will usually consist of high voltage distribution with smaller lower voltage sections managed by the equivalent of local substations. The relevance of DC or AC is rather mute in this regard, just that DC to DC converters would be used instead of transformers. I repeat, the reason cities went AC over DC was that historically practical voltage conversion and distribution was much easier using transformers.

However, with modern electronic designs, HVDC became economically practical and it has advantages over AC because there is no capacitive power loss in the DC system and the are no synchronisation issues. (read both references for further details)

There are even predictions that eventually houses will internally be powered by DC low voltage rather than AC high voltage in line with modern power usage, lighting and solar/local renewable energy which works better in a low voltage DC system.


usbg3rd (author)iTixle2012-08-20

chk out urself just need a voltmeter to do it the suprising thing is that when u try to extract power from it it goes to very low value

Zevion (author)arc862014-05-13

could you make an schematics on this description ?

Bloom212 (author)2016-04-26

A thing 2 do on a blackout is go biking for anthing you be it does not use electricity.

zoozoospetal (author)2016-01-20

For those debating the morality of this hack. I certainly agree that under normal circumstance you should never do this as it is paramount to theft. That said this technique could come in handy under emergency conditions. Often when household power is nocked out the average landline is still functioning. I could see utilizing this hack under disastrous conditions.

It could be a valuable prepper skill to have.

AllenT19 (author)2016-01-19

that old news ..there were products manufactured to run off phone line power in the 80s and you can still find some today

ThomasK19 (author)2016-01-19

Looks like paying for a bus ticket and when getting off to take some petrol from the bus' tank too. So many people with a lack of consciousness of guilt.

BurgersBytes (author)2014-04-15

To anybody questioning the need for the bridge rectifier, it is required to rectify the 90 volts AC when the phone line is called. If you get voltage on an inactive phone line then it will probably just deliver DC, but ya never know. Imagine if everybody did this! Somebody has to pay for it!

silveravnt (author)BurgersBytes2016-01-19

Exactly. It's not free. The phone company is paying for it. You know what it's called when you take somthing someone else payed for without their permision?

JoelG23 (author)silveravnt2016-01-19

The American Corporate way?

Irwini (author)silveravnt2016-01-19

You already payed for the line, so it seems still to be legal. (old phones are still working this way). What i would concern is the signal quality (strengh) on the line.

cnc_teacher (author)2016-01-19

In order for this to be "free" power, the payback time on all of the electronic parts and the LED desk lamp must be fairly short, right?

marcust13 (author)2015-12-09


محمدر (author)2015-11-14

love this

keeboudidoz (author)2015-10-09

Pretty sure you can't get too much power from a phone line as it is current limited to around 40mA. Also when you load the line, the voltage across it drops from 50V or so to about 10v or less. So, the theoretical power available would be in the neighbourhood of half a watt (0.5W) which is pretty low. By contrast, a standard USB charger provides 5W (5V at 1A).

mary hunt (author)2015-08-05

love this

richardilaner09 (author)2015-03-12

go to ' eco inplix ' - google it and learn more

jim carlson (author)2014-07-31

nice article, very innovative, petty you cant run your whole house from your phone line, but here is a page that shows you how to do that for free

dudes (author)2014-05-13

is it legal in the united states of america? specifically Ohio?

Kiteman (author)dudes2014-05-24

Try asking your phone company...

Squidyman (author)Kiteman2014-07-24

They will obviously say "yes", or at least try to convince you that it might be. Don't bother asking in the first place and do it ;)

donclark (author)2014-05-19

Very curious! Is anyone selling these as a complete kit, or something similar? I would like to use an old phone jack to power 2 usb ports or more, led night light - or ac outlet and keep the phone jack too. Or could someone point me to someone that would create it for me (for money)?

promach (author)2013-09-11

If I do not have KBP210 at my local electronic stores, what other rectifier chips can I use in place of KBP210 ?

pestopiñan (author)2013-04-04

Nikola Tesla figured this out almost 100 years ago. Supposedly the generator he devised could be made by virtually anyone. But for some reason his discovery wasn't publicized. Until recently that is. It's quite an interesting read.

The rest of it is on

milkdud55 (author)2013-04-01

Why dont you find a neigbor a outside plug and combine

i guess you couldn't power much as the phone line will have a pretty low ampage.

JerryBYong (author)2012-10-12

Hi guys, I know this instructable is kinda old but I was wanting to make this into a USB charger for my Android phone and portable charger. I currently do not have a land line registered at my home so it won't ring. So can I hook up a car charger to it?

damikethemike (author)2012-08-02

I worked for at&t. When youre disconnected from at&t, thats done via computer. that pair of wires is now up for grabs. So your pair of wires have a Pair number. it can be assigned to someone else getting services. If you have good decent quality wire (something not at all common in urban areas, to do poor quality upkeep) your pair will be used by some line tech for a trouble call of another customer needing a new pair of wire.
But if you disconnect, and no lineman takes that pair, you will still be commected at the crossbox (the big box in the area.) it has 48v coming off it. the only way THAT drops is if the Central office that the Box is running wire from, disconnects you from there. So YES that is free power. this is what I was thinking. Why cant I take the power from there, stick it into a dc to ac converter that is grid tie style, plug the AC cord from the converter into a wall socket, and Add clean power to the electrical grid...therefore get less off my electric bill?

Listen, you can get a Pay for all calls LAN line that is like 13 bucks a month. NO features. In fact, you can get a call that is only outbound. therefore no telecommunicators (at&t is KING of that mess. while working there, the COMPANY ISSUED PHONE...was always inundated with telecom calls from india talking about winning stuff!) But i feel, forget trying to run anything off it. use it as if it were a solar panel, and do what a solar panel would do.

WV_Kokamo_Joe (author)2012-04-16

What are the resistor specs? Are they 1/4 wat, 1/2 watt? +- .5 %, .o1%?

From the pictures you have posted they are 1/4 watt axial. But who knows?

You really should post this info as people going to buy these parts to build this will not know what values to get.

stealthop (author)WV_Kokamo_Joe2012-05-03

at that level 1/2 watt is plenty

stealthop (author)stealthop2012-05-03

and from what i can tell from the poor picture qual , they are 10% tolerance

smuhammad5 (author)2012-04-18

If we get 12volts DC by voltage divider.Can we provide that to a power inverter means UPS??????
plzzzzzzz answer me

WV_Kokamo_Joe (author)2012-04-16

Also, what is the voltage and amps acheived?

Maccer (author)2010-12-10

Is this legal?

Taddle (author)Maccer2012-04-13

Depends where you live

tinstructable (author)2010-12-21

Depending on how much your phone draws, couldn't you technically power your phone just off of this?

Taddle (author)tinstructable2012-04-13

Older phones did actually use the power from the phone line

Super_Nerd (author)2011-08-11

Technically, this isn't completely free, because phone service isn't free. However, there isn't any extra cost, so I would say...

Money saving hidden electricity

About This Instructable




Bio: Tinkerer, hackster and prankster. Hit me up on Facebook: Thanks for checking out my Instructables!
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