Archive for the ‘Joule Thief SMPS DC-DC’ Category:

2017-08-19 Emitter Base Breakdown Can Damage Transistor 

From YT reply to Neilgn  2017-08-20 Take any NPN transistor and measure the gain, and write it down.  Then put a 1k resistor in series with the transistor’s emitter and connect the emitter to positive and base to negative of a power supply.  Adjust the voltage until 2 or 3 volts are across the 1k

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2017-06-08 AD Has ADP5090

Ever since I’ve been experimenting with Joule Thiefs I’ve done so with the intention of using the circuit for boosting a low voltage source to power a higher voltage circuit.  So I think this Analog Devices ADP5090 is very useful for doing just that: powering circuits up to 200 mW from very low voltage power

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2009-01-10 Experimental Joule Thief

Date 2017-01-12 Link to Experimental Joule Thief

2016-10-18 FM Transmitter Uses Power MOSFET

I watched this YouTube video where the author shows his FM transmitter using a big 60 volt power MOSFET. He also shows a very readable photo of the schematic. The video was made several years ago in 2012. He is powering this transmitter by connecting it to eleven 9 volt batteries in series, totalling 99

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2016-10-04 Joule Thief Powers Field Strength Meter

There are many circuits that are used infrequently that are powered by the usual 9 volt battery. One of these happens to be a field strength meter (FSM), which is used for detecting the power output of a transmitter such as the one a radio amateur uses. Some FSMs are very simple and use no

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2016-09-28 Battery keeps Joule Thief Lit

I put this AA cell, which measured 1.3 volts – ‘dead’ – on one of my germanium Joule Thiefs more than a week ago. It was glowing very brightly for a few days. For the last few days, it has been weakly glowing, and the Kirkland AA cell is still hanging in there, even though

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2016-09-06 Supercharged JT Shutoff

I had a hard time editing the reply to #2 of the comment, besides it’s a good blog. The following applies to my Supercharged Joule Thief. But you really don’t need to use a MOSFET. Any PNP transistor, 2N3906 or BC557, will do the job, and the current will be relatively low. Replace the diode

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2016-06-05 Toroid Cores 10 mm .4 Inch Green

I was on eBay and saw some small green ferrite toroid cores, ten for 99 cents including shipping.  I figured that since I had bought some larger green cores a few weeks ago and liked them, I couldn’t go wrong buying these since they were less than ten cents apiece. They were sent from an

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2016-05-16 Tape Wound Toroid Core From Surplus Sales

Long ago I built DC-DC converters using a toroid made with tape wound core. The cores were about 2 inches O.D. and we used regular 12 AWG solid insulated house wire for the primary windings. Even so, these cores vibrated a lot at several hundred Hz, making a screeching noise. I saw some very small

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2016-02-23 Joule Thief With Daylight Shutoff

I designed my Blue Blinky with a daylight shutoff, using a LED as the light sensor and an additional transistor to amplify the minuscule current that the LED puts out.  This worked just great because there is the point across the timing capacitor where the current is very low, and it takes very little current

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