Joule Theif
HELLO EVERYONE,
THIS IS ABOUT JOULE THIEF, ITS QUIT EASY TO MAKE IT.
AS ITS REALLY COMMON, THE CONSTRUCTION IS REALLY EASY BUT IT MAY BE TAKE FOR YOU TO GATHER PARTS OF IT.THE MOST IMPORTANT ONE IS TOROID, I GOT IT FROM AN OLD SMPS. LATER I WILL TELL HOW TO GET IT AND I AM ALSO GOING TO TELL YOU ITS ALTERNATE.
HOW A JOULE THIEF WORKS:
The joule thief works at a range of voltages down to 0.35 volts.
When the circuit is switched on, charge flows into the base
of the transistor switching it on. (The size of this current
is limited by R1). This causes a larger current in the righthand
coil which bypasses the LED as it goes through the
transistor. Wires that carry a current produce a magnetic
field which is made stronger by coiling the wire around a
ferrite core. Energy is stored in the magnetic field.
The lefthand coil, being wound on the same core as the righthand coil experiences this build up of a
magnetic field in the ferrite core. This change in magnetic field in the lefthand coil generates a
current pulse in it in opposition to the original base current - effectively causing the transistor to
rapidly switch off, which in turn switches off the current in the righthand coil. The magnetic field
collapses and, as it does so, the magnetic energy stored in the coil is converted into electrical energy
resulting in a high voltage spike across the coil terminals. This voltage spike is enough to cause
conduction in the LED and produce a short burst of light.
With the magnetic field collapsed, the process repeats itself. The time between the voltage spikes is
shorter than the persistence of vision so the LED appears to be permanently on.
SO, I HAVE DESIGNED MY OWN CIRCUIT AND I WILL ALSO GIVE CIRCUIT.
SO THE MATERIALS ARE-
ANY NPN TRANSISTOR (2N SERIES WORKS WELL)
TWO DIFFERENT COLOR THIN WIRE OR COPPER WIRE (THIN ONE WORKS WELL)
1 KILO OHM RESISTOR
SMALL TOROID (FERRITE WOKS BETTER): YOU CAN ALSO USE DIFFERENT, NO PROBLEM......I GOT MY TOROID FROM AN OLD CFL. IT WORKS WELL.
IF YOU CANT FIND IT, GET A CENTER TAP TRANSFORMER(SMALL ONE:240V-6V)
OLD 1.5 VOLT CELL
ANY COLOR LED.
Step by step construction of the Joule Thief
Now we have done our homework and we have the knowledge to build our Joule Thief circuit.
Step 1 – Wound the Toroid
Take the two strands of plastic insulated wire and hold them together. Start off by sticking then through the middle of the toroid until you have 2 cm of wire left to make a connection with later. Keep the two wires together and wrap them around the toroid until you have covered the whole toroid. If you have wire left you can continue until you have about 2 cm of wire free on either side. Remove about a 0.5 cm of the plastic insulation on all four of the wires as in the photo. You have now wound your toroid and we are ready to continue.
Step 2 – Join the two coils of Toroid
The
next step is to join the two coils or windings of the toroid. You may
have noticed the two dots next to the toroid windings in the circuit
diagram. These two dots indicate the polarity of the transformer and as
you can see the two windings are opposite to each other. To make sure
that the polarity of our toroid windings are correct we must do the
following:
With the toroid sorted it is time to build the rest of the circuit. Using you transistor diagram and the LED configuration it should be easy to finish the circuit on breadbord or solder the components together. An easy way to remember the LED configuration is to remember that the flat side of the LED is the same as the cross bar in the LED symbol, so the arrow side is the round side of the LED.
Step 4 – Switch On
After you have completed the circuit it is time to switch on and if you have done every thing right you should have something like this.
CONGRATS IF IT WORKS.
NOW THIS IS MY CIRCUIT-
THE ONLY THING THAT I AM CHANGING IS THAT TRANSFORMER.
AS I TOLD YOU THAT TRANSFORMER ALSO WORKS, SO JUST REPLACE TOROID WITH A TRANSFORMER.
HERE IS A VIDEO, FOR A BETTER UNDERSTANDING-
http://www.youtube.com/watch?feature=player_detailpage&v=OyJwZv94O48
and this is my video if simple joule thief-
http://www.youtube.com/watch?v=GH50cXAwu4k
THIS IS ABOUT JOULE THIEF, ITS QUIT EASY TO MAKE IT.
AS ITS REALLY COMMON, THE CONSTRUCTION IS REALLY EASY BUT IT MAY BE TAKE FOR YOU TO GATHER PARTS OF IT.THE MOST IMPORTANT ONE IS TOROID, I GOT IT FROM AN OLD SMPS. LATER I WILL TELL HOW TO GET IT AND I AM ALSO GOING TO TELL YOU ITS ALTERNATE.
HOW A JOULE THIEF WORKS:
When the circuit is switched on, charge flows into the base
of the transistor switching it on. (The size of this current
is limited by R1). This causes a larger current in the righthand
coil which bypasses the LED as it goes through the
transistor. Wires that carry a current produce a magnetic
field which is made stronger by coiling the wire around a
ferrite core. Energy is stored in the magnetic field.
The lefthand coil, being wound on the same core as the righthand coil experiences this build up of a
magnetic field in the ferrite core. This change in magnetic field in the lefthand coil generates a
current pulse in it in opposition to the original base current - effectively causing the transistor to
rapidly switch off, which in turn switches off the current in the righthand coil. The magnetic field
collapses and, as it does so, the magnetic energy stored in the coil is converted into electrical energy
resulting in a high voltage spike across the coil terminals. This voltage spike is enough to cause
conduction in the LED and produce a short burst of light.
With the magnetic field collapsed, the process repeats itself. The time between the voltage spikes is
shorter than the persistence of vision so the LED appears to be permanently on.
SO, I HAVE DESIGNED MY OWN CIRCUIT AND I WILL ALSO GIVE CIRCUIT.
SO THE MATERIALS ARE-
ANY NPN TRANSISTOR (2N SERIES WORKS WELL)
TWO DIFFERENT COLOR THIN WIRE OR COPPER WIRE (THIN ONE WORKS WELL)
1 KILO OHM RESISTOR
SMALL TOROID (FERRITE WOKS BETTER): YOU CAN ALSO USE DIFFERENT, NO PROBLEM......I GOT MY TOROID FROM AN OLD CFL. IT WORKS WELL.
IF YOU CANT FIND IT, GET A CENTER TAP TRANSFORMER(SMALL ONE:240V-6V)
OLD 1.5 VOLT CELL
Step by step construction of the Joule Thief
Now we have done our homework and we have the knowledge to build our Joule Thief circuit.
Step 1 – Wound the Toroid
Take the two strands of plastic insulated wire and hold them together. Start off by sticking then through the middle of the toroid until you have 2 cm of wire left to make a connection with later. Keep the two wires together and wrap them around the toroid until you have covered the whole toroid. If you have wire left you can continue until you have about 2 cm of wire free on either side. Remove about a 0.5 cm of the plastic insulation on all four of the wires as in the photo. You have now wound your toroid and we are ready to continue.
Step 2 – Join the two coils of Toroid
The
next step is to join the two coils or windings of the toroid. You may
have noticed the two dots next to the toroid windings in the circuit
diagram. These two dots indicate the polarity of the transformer and as
you can see the two windings are opposite to each other. To make sure
that the polarity of our toroid windings are correct we must do the
following: - If we look at the toroid we noticed that we have two wires of different colours sticking out at both ends of the toroid.
- Take one wire of a specific colour (green in the example) on the one side of the toroid and one wire of the other colour (white in the example) on the other side of the toroid and connect (or solder) them together. These two wires forms the top pole of the toroid as in the circuit diagram and is connected to the positive terminal of the battery.
With the toroid sorted it is time to build the rest of the circuit. Using you transistor diagram and the LED configuration it should be easy to finish the circuit on breadbord or solder the components together. An easy way to remember the LED configuration is to remember that the flat side of the LED is the same as the cross bar in the LED symbol, so the arrow side is the round side of the LED.
Step 4 – Switch On
After you have completed the circuit it is time to switch on and if you have done every thing right you should have something like this.
CONGRATS IF IT WORKS.
NOW THIS IS MY CIRCUIT-
THE ONLY THING THAT I AM CHANGING IS THAT TRANSFORMER.
AS I TOLD YOU THAT TRANSFORMER ALSO WORKS, SO JUST REPLACE TOROID WITH A TRANSFORMER.
HERE IS A VIDEO, FOR A BETTER UNDERSTANDING-
http://www.youtube.com/watch?feature=player_detailpage&v=OyJwZv94O48
and this is my video if simple joule thief-
http://www.youtube.com/watch?v=GH50cXAwu4k
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