Introduction: Wireless Electricity Transmission Circuit

Picture of Wireless Electricity Transmission Circuit

This is a simple circuit that can power a light bulb without any wires, at a distance of almost 1 inch! This circuit acts as both, step up Voltage converter and also wireless electricity transmitter and receiver. This is a really easy project to do, and could be used in many ways if improved. So lets get to it!

Step 1: Materials and Tools Necessary for the Project

Picture of Materials and Tools Necessary for the Project

So to make this circuit you will need:

1) NPN Transistor. I used 2N3904 but you could use any NPN transistor. Most commonly you could find BC 337, BC547 etc. (Any PNP transistor would work, just reverse the polarity of the connections.)

2) Magnet wire or insulated wire. About 3-4 feet of wire or less should be enough. (Magnet wires are just copper wires with very thin enamel insulation) You could find wires from most electronics, like transformers inside CFC Bulbs, inside speakers, inside motors, inside relays etc.

3)Resistor 1 Kilo Ohm. This resistor would be used to protect the transistor from burning out in case of overload or excess usage ad heat. You could use higher values upto 4-5 Kilo OHM. You could even decide not to use a resistor, but that would draw in more amps, thus draining your battery faster.

4) L.E.D light . I used a 2 mm Ultra Bright White L.E.D. You could use any L.E.D (Light Emitting Diode). For this circuit, the L.E.D only shows the circuit in action.

5) A 1.5 Volt AA Battery . ( Do not use batteries of higher voltage unless you want to damage your transistor.)

Tools needed:

1) Scissors or knife.

2) Soldering Iron (Optional). If you don't have a soldering iron, you could just twist the wires and leads for connection. That's what I used to do when I didn't have soldering iron. If you want to try the circuit on solderless breadboard, you are good to go.

3) Lighter (Optional). We will be using lighter to burn off the insulation from the wire, then just use a scissor or a knife to scrape off the insulation.

Step 2: Watch the Video to Learn How to Make It!!

Step 3: Recap of the Steps

So first of all you need to take the wires, and make a coil of 30 turns around a round object. Name this coil A. With the same round object, start coiling again. This time when you make your 15th turn with the wire, create a tap, and then coil another 15 turns. So now you have a coil with two ends and one tap. Name this coil B. Tie knots on the ends of the wires, so that it doesn't uncoil by itself. Burn the ends and the tap in order to take off the insulation from both the coils. If you don't want to use a lighter, use a scissor to scrape off the insulation from the ends of the wires and the tap. Make sure, the Diameter and number of turns on the coils are equal!!

Making the transmitter: Take the transistor, and place it so that the flat side is facing up and the leads are facing towards you. The lead on the left is the Emitter, the lead in the middle is Base, and the lead in right is the Collector. Take the resistor and connect one of its ends to the base of the transistor. Take the other end of the resistor and connect it one of the ends (not the tap) from Coil B. Take the other end from Coil B and connect it to the Collector of the transistor. If you want you could connect a small piece of wire to the Emitter of the transistor (It would work as an extension of the Emitter.)

Making the receiver: To make the receiver, just take Coil A and connect its ends to the leads from the L.E.D.

You are done making the circuit!!

Step 4: Circuit Schematic

Picture of Circuit Schematic

Here is the schematic of the circuit. If you don't know anything about schematics, don't worry. In the next steps a diagram is provided.

Step 5: Circuit Diagram

Picture of Circuit Diagram

So here is the diagram of the circuit.

Step 6: Using the Circuit

Picture of Using the Circuit

Just take the tap from coil B and connect it to the positive end of the battery. Connect the negative end of the battery to the Emitter of the transistor. Now if you bring coil A with the L.E.D close to Coil B, the L.E.D lights up!

Step 7: What Is the Science Behind This?

(I am just trying to explain the science behind this in simple words and analogies, and I know I am going to make mistakes. In order to provide the correct explanations I need to go into details, which I am unable to , so I am just gonna use common analogies for explaining the circuit ).

The transmitter circuit that we just created is an Oscillator circuit. You may or may not have heard about the Joule thief circuit which has striking resemblance to this circuit. A joule thief circuit, takes electricity from a 1.5 Volt battery, outputs electricity at a higher voltage but with thousands of intervals in between. A L.E.D requires 3 volts to light up, but a joule thief circuit could light up the L.E.D with 1.5 volt battery. So the Joule Thief circuit is known as a step up converter and also an oscillator. The circuit that we created is also an oscillator and step up converter. But the question might be, "How does it light up the L.E.D at a distance?" This happens due to induction. Lets use transformer for example. A normal transformer has a core with wires on either side. Lets suppose the wire on each side of the transformer is equal in amount. When electricity is passed through one coil, the coil becomes an electromagnet. If the electricity is oscillating voltage, that means the voltage would keep rising and dropping. So when an oscillating electricity is passed through the coil, the wire gains properties of electromagnet and then again loses electromagnetism when the voltage drops. A coil of wire becoming electromagnet and then losing its electromagnetic characteristics really fast is just like a magnet moving really fast in and out of the second coil. And when you pass a magnet really fast through coil of wires, you produce electricity, so the oscillating voltage in one coil on the transformer, induces electricity in the other coil of wire, and thus wirelessly electricity is transferred from one coil to the other. In our circuit, the air is the core, and there is oscillating voltage going through the first coil, so you induce A.C electricity in the second coil and light up the bulb!

Step 8: Uses and Tips for Improvements!

So for our circuit we just used a L.E.D to show the output. But we could do more than that! The receiver circuit receives A.C electricity, so we could use Large step up converter to use the output from the receiver coil to light up CFC bulbs! Also it is great for some cool magic tricks, fun gifts,and science projects for class. Also you could change the diameter of the coils and number of turns on the coils to maximize the results. Also you could try making pancake coils, and see how it goes! The possibilities are endless!!

Step 9: Troubleshooting

So this are the variations of problems you may face, and how to fix them:

1) Problem: The transistor becomes too hot!

Solution: Did you use a resistor of the right value? I didn't use a resistor the first time, and it started to smoke. If it does not solve the problem, then try using a heat shrink or using a transistor with higher amp rating.

2)Problem: The light does not light up!!

Solution: The problem is too broad. There could be many reasons behind the problem. But first check the connections. I accidentally swapped the Base and Collector connections, which caused a big problem for me. So check you connection first. If you have a multimeter check to see if you have continuity between your connections. Also make sure that the coils are of the same diameter. Also be careful there no shorting in the circuit.

I don't know about any more problems. But if you are facing some other problems, let me know! I will try to help as much as I can. Also I am a 9th grader, so my scientific knowledge is extremely limited, and so if I make any mistakes, help me find it out. Suggestions for improvements are more than welcome. Good Luck with your project!!!


john henry made it! (author)2015-08-03

thanks for the simple schematic.
I added a zenner diode on the receiver coil and i get +-20V 3mA+- DC. from the one 1.5V battery.
otherwise without the diode my multimeter wouldn't pick up a DC reading.
I used 32AWG wire because thats all i had. everything else is the same as the instructable.
sorry for the crappy lighting in the picture ps vita doesn't have a flash...
what voltages is everyone else getting?

Ramu Chand (author)john henry2015-08-05

Hey john, could you give me the correct schematic of your project?

john henry (author)Ramu Chand2015-08-05

well heres my version of the schematic.
To be clear the receiver coil is only soldered to a 2 pin connector in the v2 on the schematic.
I included part numbers for most of the parts. I figured the LED part number isn't necessary. Its just a red LED. which is the one i grabbed.
Also i used 28.3mm coils. I wrapped it around an M&M minis tube. lol

Ramu Chand (author)john henry2015-08-06

Hey dude, what software do you use to prepare the schematic diagram?

Do you know any ways to increase the length of the transmission????

john henry (author)Ramu Chand2015-08-06

oh i just used digikey's online software. It was quick and easy.
you can right click a component and add custom info, then drag it around to look nice.

(sorry for the length...)
As far as transmission length goes I'm not 100% sure. how much power you transfer depends on supply voltage and current to the transmitter coil. probably obvious...
For my setup (32AWG magnet coil 28.3mm diameter) using a 1.5v ~230mA battery gets me (~24v, 3mA, 0.072Watt) point blank, and about 5v ~30mm, 1.5v ~35mm distance with a dimly lit LED. as you might have figured the voltage drops off quickly with distance.
Using a better power supply and higher current it lights up a little better but stills cuts out at over 35mm.
At 3V input i get (~40-50v ,~7.5mA, ~0.3375 Watt) point blank to the receiver coil and the LED cuts out at almost 40mm. also at 3V 30mm i get 5v 0.20mA.
At 4.5V i get (~60-75v ~7.2mA, ~0.504 Watt) point blank the LED cuts out after 30mm but is actually nicely lit at ~30mm. so for charging a cellphone mine could possibly do 30mm at 4.5V but would probably take a long time. I'm not 100% sure on charge time as it depends on battery capacity. but my cell charger is 5.1V 700mA 3.57Watt so i would suspect so. lol
after 4.5v more voltage seems to make it worse. probably because the transistor warms up quite a bit. a different coil and/or wire size might give better or worse distance.
The 2N3904 transistor's base is only rated for 6V by its manufacturer specs.
I haven't played around with different resistances but it probably wont help much.... not too sure at least for distance i wouldn't expect it too get much better.
I couldn't tell you exactly how to get a certain distance, but i hope this info helps.and wasn't too confusing or lengthy. i did some "on the spot" experimenting. lol
you could find better schematics that offer better power transfer, but most likely have small distances. my power supply Over loads my multimeter's amperage reading so i have no idea what its at. Experiment a bit if you can it helps understand a circuit and its limits.

To answer your question further. More distance is actually hard to get with coils. Qi wireless charging only manages 45mm with their system. I'm not sure exactly what their specs or schematic are though.
MagMIMO uses a bit different system similar to how some long range wireless router works. it gets up to 30cm by directing a magnetic field like a beam. this technique gives you the freedom to move your phone around instead of having it flat directly above the charging coil. I couldn't tell you how it works but if i did i would make one myself. lol

robotnerd (author)john henry2017-10-29

Hi John,

Got the led lit. Now want to measure the voltage, but having trouble. Will the ac setting on DMM not work? Do I have to use diode?


john henry (author)robotnerd2017-10-31

are you trying to mesure ac?
the diode is used to mesure dc on the receiver cuircut. it shouldnt need one for the led to work as it is a diode but to mesure the voltage yes you would otherwise you bypass the led and get ac thruough the test leads.
that's why i added a redundant diode in my version.

robotnerd (author)john henry2017-11-02

I purchased a better DMM, but when I connect the 2 leads across the lit led, I get only 1.4 mv.

SunnyC26 (author)Ramu Chand2016-08-05

well using a redesign coil for emission
you must make a pie coil that should give you about 30 cm transmission

argha halder (author)john henry2015-08-08

Great job!! And thanks for the measurements, I could not get mine because my meter doesn't have its batteries right now. But still impressive job with the measurements!!

Mine is not working

I use a 36 gauge magnet wire
Transistor 2n2222,2n3904,bc547
And all the things you mention so why mine is not working

Did you properly remove the insulation from the wire? And also post a picture of the circuit, because from your description it is really difficult to give a proper solution to the problem.

soepaineoo (author)argha halder2016-10-19

Have a formula
of receiving coil?

pcarew (author)john henry2015-08-11

Just a small clarification, 1N4148 isn't a 'Zener' diode, it's just a regular high speed switching diode. By adding it into the circuit, you're half wave rectifying the AC signal to a DC signal which is why you can now measure it with a DC multimeter

john henry (author)pcarew2015-08-12

Most of the labeling is worn off as well so I'm not 100% sure if that was the correct number. I couldn't find one that had 100% of the label intact...
I know its not a Black signal diode. or clear point contact or crystal diode..
and yes I know how diodes work thats why i said i needed one to measure in DC... thats just all i have right now.  Zener_Diode.JPG

BurgersBytes (author)2015-04-09

Here's the corrected schematic.

Thanks for the correction!

samaddon (author)argha halder2016-04-30

Hey there little friend , i should have directly commented on your post but am replying for a reason , the circuit you gave is very correct up to your level (the circuit given by the burgersbite is just an cleaner representation of yours) and i gotta say you explained that stuff pretty well , in a bit more technical terms , the oscillator you've made acts like a feedback oscillator and when you put the receiver coil above it , what actually happens is mutual induction , or the rate of change of flux in the first coil results in the induced E.M.F in the other other coil.The higher the frequency of the oscillator the higher voltage you get , singe e=-d(flux) / dt , the smaller time it takes for one oscillation the higher emf you induce but sadly there is a factor which limits you to get 1000000 volts out of that battery , it is the more voltage to gain up , the more current you'll loose and at some point there will be negligible current through the second coil though the voltage is pretty high. So you cant put up good voltage with that battery. So my point was you're explanation of this circuit was mind blowing and super easy to understand. Keep up the good work kid.


Samad Haque

Maria230 (author)argha halder2016-04-08

How many leds in parallel can it carry?

khyalia (author)argha halder2016-01-13

hey as magnetic flux through the coil is not changing (as we keep coils at constant distance) how can led keep glowing?

You can swap it with the one you had if you wish. All I did was edit it with Paint. The 15 came from the 1.5 volts lol.

From this schematic the current in both coils flow in the same direction, right?

However, take a look at the video when he turn the coil, it look like the current will flow in opposite direction.

adarsh n m (author)BurgersBytes2015-10-07

if we put two wireless current in opposite side what will happen?

adarsh n m (author)BurgersBytes2015-10-07

if we put two wireless current in opposite side what will happen?

adarsh n m (author)BurgersBytes2015-10-07

if we put two wireless current in opposite side what will happen?

adarsh n m (author)BurgersBytes2015-10-07

if we put two wireless current in opposite side what will happen?

QJ Neo (author)BurgersBytes2015-04-15

What software you use to draw the schematic diagram ?

CoderPranav (author)2017-09-28

Is there any reason for 30 turns or is an arbitrary number fine?

iceng (author)2017-07-01

no resonance

Dheeraj SaiG (author)2017-03-26

is it practically possiable to do.can i try it with 30 gauge copper wire ,22k resistor ,2222Atransiator and 9volts supply

AnupamaD1 (author)2017-02-20

can i use MJE 3055T NPN TRANSISTOR


ÖzgürD9 (author)2017-02-18

How can i put a 3v dc motor in receiving coil? I tried to use a diode bridge but it didnt work, should i use a capacitor?

Hassan BinU (author)2017-02-17

Great engineers i need your assistance i want to convert AC 220 to DC 220 without rectification. Your favour is needed i have tried to do but I didn't get it

Nikkhin (author)2017-02-02

Sir, can I get 12v transmitter and reciver circuit schematic??plz email me...

Techno GeekK (author)2017-01-22

could it be used to make a phone wireless charger .
changing the battery to a wall charger . higher transistor etc.
would it possiblely work?

ragu2003 (author)2016-12-26

i made it. i have got third prize in my expo.

Please post a photo of yours and what transistor you are using? I am asking this because mine is failed. Please reply

Chandan Kolaparthy (author)2017-01-05

It didn't work for me.
I used BC547 and 32 guage enameled copper wire with 1 kilo Ohm resistor. See the pictures and reply quickly.

etoolmilitaria (author)2016-12-17

This is incredibly interesting. Judging by many of the comments below many are interested in increasing the power output and range for more practical household uses. Personally Im interested in building a device that would allow me to have a wall outlet tap as the transmitter and a receiver that I would be able to plug several common household lower-wattage devices into. Any interest in creating more tutorials going in this direction? Is there a general formula for increasing the voltage and transmission distance beyond the diagram you created? It would make sense to me that this would be possible so long as the ratios are kept the same. Thank you.

Also Im wondering if anyone in this thread have attempted to create such a device?

mohd hashir (author)2016-12-15

this project is very good

argha you are super intelligent

mohd hashir (author)2016-12-15

where you live argha...??tell me please

Bhoomika1999 (author)2016-12-12

My transistor is getting hot but the circuit is not working. I have used 9v battery,2n2222 transistor,1k resistor

ragu2003 (author)2016-11-22

i used

-cdil2n2222a transistor

-9 volts

-first coil of 44 turns

second coil of 30 turns

-5k resistor

but it doesn't works

argha halder (author)ragu20032016-12-09

Could you post a picture of it? Otherwise it is really hard to tell.

colin55 (author)2016-05-04

The way the
circuit works is very complex.

It starts when the transistor is off.

Current flows through the 15 turns of the winding and through the 1k resistor,
into the base of the transistor. The
transistor turns on slightly and produces a current in the other 15 turns and
produce magnetic flux.

This flux cuts the 15 turns in the winding to the base and produces a voltage
that adds to the voltage produced by the battery.

This increases the current into the base of the transistor and the transistors
turns ON more.

This continues and the transistor turns on more and more until it cannot turn
on any harder.

At this point the magnetic flux in the collector winding is a maximum but is
not expanding flux and thus the base winding does not produce any additional

The current into the base of the transistor reduces and the transistor turns
off slightly.

The current through the collector winding reduces and the magnetic flux starts
to collapse and produce a voltage (in both windings) of opposite polarity.

In the base, it starts to turn the transistor off completely and in the collector
winding the magnetic flux is quite considerable because it is collapsing very
quickly and it radiates this magnetic energy to the air.

When you put another coil near the first coil, the magnetic energy passes
through the centre of the coil and produces a voltage in the turns.

This voltage can be as much as one volt per turn but when the voltage reaches
the characteristic voltage of the LED, the energy (consisting of voltage and
current) is converted to a CURRENT and the LED illuminates. You can put 2 LEDs
on the receiving coil to see the voltage it produces.

The circuit will be much more efficient if the 1k resistor is placed before the
base winding and a 1n to 22n connected between the 1k and negative of the
battery. Try this and the brightness
will increase and the current from the battery will decrease!!



AndreiF23 (author)colin552016-12-06


You tell us about improving the circuit. Can you draw the circuit schematic?


SunnyC26 (author)colin552016-08-05

THANKS!! for the explanation sir it really helped me in queries

DenizG1 (author)2016-12-05

can i use 0.6 mm or 23 awg wire for coil

ragu2003 made it! (author)2016-11-30

thaks a lot

About This Instructable




Bio: I love making and breaking electronics.
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