tag:blogger.com,1999:blog-8226950546477403054.post1122108832358622800..comments2017-06-25T12:02:05.934+05:30Comments on Electronic Circuit Projects: Making a Joule Thief Charger CircuitSwagatamnoreply@blogger.comBlogger8125tag:blogger.com,1999:blog-8226950546477403054.post-61769383018835434562014-02-11T23:50:41.688+05:302014-02-11T23:50:41.688+05:30Iron powder toroid's can be used, and so can a...Iron powder toroid's can be used, and so can air core coils. They don't have high permeability, so they need more turns to have the same inductance as ferrite. 5 meters or 16 feet of telephone wire wound around a AA cell will work, but it's much larger and has a higher DC resistance. Some powdered iron cores are big, too, and more difficult to wind, so the air core coil may be a quicker way to get the JT running.Watson aNamehttp://www.blogger.com/profile/05401450358035283373noreply@blogger.comtag:blogger.com,1999:blog-8226950546477403054.post-38481755200425803142013-07-20T11:46:43.313+05:302013-07-20T11:46:43.313+05:30good explanation, thanks!good explanation, thanks!Swagatam Majumdarhttp://www.blogger.com/profile/13783312838408713408noreply@blogger.comtag:blogger.com,1999:blog-8226950546477403054.post-40136102680808840352013-07-19T21:04:54.773+05:302013-07-19T21:04:54.773+05:30In Joule Thief, the primary coil (the one that sto...In Joule Thief, the primary coil (the one that stores and carries almost all currents is the one that is connected from the positive rail to the transistor's collector) is one of the most important part besides the transistor. As you might know, if the resistance of the primary wire is 1 ohm, and 1V across it, and 1A of current is flowing, then the wire is dissipating 1W of energy. Now, a 1.5V battery current can reach upto a half amp or more. Therefore, the resistance of this primary coil must be low to let the current flow freely to your LED instead of being wasted in higer resistance. In order to make the resistance low in your primary coil, the winding wire can be then chosen wisely. For instance, according to the data sheet, copper wire of 30AWG has 0.104 ohm/ft. resistnace whereas 24AWG has 0.0257 ohm/ft resistance. And the last part to determine how many turns, you have to think about the amount of energy you want to store in your primary coil (or inductor). The amount of energy stored in this primary coil is equal to the one half of the inductance (L) times the current (I) squared, that is L/2*I^2. Now, the supply voltage remains the same across the Joule Thief coil, you can increase the energy stored by using fewer turns. <br />In a nutshell, doubling the inductance (that is, higher number of turns), doubles the energy stored but lowering the inductance (that is lowering the number of turns) by half, the resistance is lowered by half, that means doubling the current, the energy quadruples. Hope, this will let you determine the number of turns depending on the demand of your load (wheather you want to light a single typical 5mm LED that needs only 20mA current or a 1W LED that requires 350mA current). Maya Bhttp://www.blogger.com/profile/00497113310467387927noreply@blogger.comtag:blogger.com,1999:blog-8226950546477403054.post-57234035801803997492012-08-11T12:22:06.805+05:302012-08-11T12:22:06.805+05:30Can I use iron powdered toroid, instead of ferrite...Can I use iron powdered toroid, instead of ferrite toroid?, b'cause it's hard to get 1" diameter toroid here.Blumoonhttp://www.blogger.com/profile/00758949487201545670noreply@blogger.comtag:blogger.com,1999:blog-8226950546477403054.post-112745291743803642012-07-08T20:52:13.120+05:302012-07-08T20:52:13.120+05:30I don't know the exact data, you may try the ...I don't know the exact data, you may try the number of turns by trial and error, the one which produces brightest of lights and consumes minimum current is the right one.Swagatamhttp://www.blogger.com/profile/07642660295491415749noreply@blogger.comtag:blogger.com,1999:blog-8226950546477403054.post-37979164600699153732012-07-06T11:39:25.001+05:302012-07-06T11:39:25.001+05:30thanks for the reply.i have one more doubt. i have...thanks for the reply.i have one more doubt. i have gone thru many joul thief ckts. but no: of turns shown in varios ckt are different. what is the relation ship with no: of turns to the o/p voltage & current?can you post an ideal circuit with maximum efieiency and explanation plsvineeshhttp://www.blogger.com/profile/10331442582047384058noreply@blogger.comtag:blogger.com,1999:blog-8226950546477403054.post-60313132865513817902012-07-06T10:37:32.414+05:302012-07-06T10:37:32.414+05:30Yes it can be. It's basically done with the he...Yes it can be. It's basically done with the help of the coil and the induced frequency. During the zero pulse sections of the frequency, the coil kicks stepped-up voltage to the LED and makes it glow even at lower supply voltages.Swagatamhttp://www.blogger.com/profile/07642660295491415749noreply@blogger.comtag:blogger.com,1999:blog-8226950546477403054.post-62169229514352021652012-07-04T17:14:15.905+05:302012-07-04T17:14:15.905+05:30is it possible to boost the voltage and current fr...is it possible to boost the voltage and current from other than a battery source using joul thief ckt?if i have a 1.5 v dc using a transformer is it possible to boost? or this crkt is just for battery ? can you pls explain the working principle?vineeshhttp://www.blogger.com/profile/10331442582047384058noreply@blogger.com