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Questions tagged [joule-thief]

voltage boosting circuit.

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How to light up a rocker switch powered by a battery of only 1.5v?

I have a small hobby project for which I wired 4 AA batteries in parallel to achieve the desired result, which comes to 1.5V, as the batteries are in parallel, which is what works for my project. My ...
electrical's user avatar
0 votes
3 answers
165 views

Joule thief circuit [closed]

I wonder why LED1 is turned on in the Joule Thief circuit and wirelessly connected LED2 is not. Someone said "In Joule thief circuit the transformer is wound around a ferrite core. This is to ...
abeloejmn's user avatar
4 votes
2 answers
764 views

Please offer comments, critique on self-resonating invented buck joule thief converter for third world use [closed]

Even though I'm not an EE, I have simulated the Joule Thief to death in LTSpice, but I have not yet made a prototype of this circuit. I have a friend who is an EE who won a contract to light some ...
MicroservicesOnDDD's user avatar
1 vote
2 answers
143 views

How do I produce more even output with a 6V Joule Thief?

For my 6V Joule Thief, it starts out too bright, and gets too dim towards the end of its battery life (about 3V). How can I improve this?
MicroservicesOnDDD's user avatar
2 votes
3 answers
489 views

How to reduce NPN reverse base current on this interesting "Super Efficient Joule Thief"?

Note: The question part is the fixing of the negative current at the transistor base. It looks like there's a problem with negative current at the LED(s) -- this is not expected to be answered in this ...
MicroservicesOnDDD's user avatar
3 votes
3 answers
513 views

How can I measure the output of a voltage booster circuit?

I made this circuit, which was described on-line as a "transformerless Joule Thief." I was able to light four LEDs of varying forward-voltage in series, but I couldn't figure out how to use ...
Annette Gates's user avatar
10 votes
2 answers
340 views

Is a balancing diode really necessary for the Balanced Boost converter?

Please pardon all of the information that precedes the question -- I didn't want you to actually have to go read the paper itself. This question is in two parts, but they are really equivalent, so it'...
MicroservicesOnDDD's user avatar
62 votes
3 answers
10k views

Is this video fake? I thought Tesla coils only worked on AC

This video shows a 9-volt battery connected to a wire as a primary. The first reason I think this is fake is that he is powering a Tesla coil with 10 volts. The second reason is that Tesla coils work ...
Gabriel ashmore's user avatar
1 vote
3 answers
1k views

How to design a boost converter? (1.5V to 4V)

I want to build a circuit that powers 2 standard red LEDs (forward voltage of 2V each) from 1 AA battery. I would like to learn how to design and build a boost converter that can take 1.5V in and ...
Adam's user avatar
  • 25
1 vote
1 answer
196 views

How to use YX8122 led driver?

I am building a small LED lamp from a jar(about 100ml), so all components should fit in it. I decided to use a LED drive/Joule Thief, that I found at online Chinese store. Datasheets (all I can find ...
Shiftas's user avatar
  • 11
3 votes
2 answers
1k views

Using a Peltier element to power an Arduino

I got myself a Peltier element and want to use it for an IOT project. What is the best way to use the Peltier in order to power an Arduino or something similar every few minutes? (For my project it ...
Michael Brown's user avatar
1 vote
4 answers
1k views

Can I charge a super capacitor with a MPPT?

I already did some testing. I have a 220mW solar panel that charges a 3V supercap (takes a long time) which eventually powers my wifi module that needs ~1.5W (1.5 J/s) for 1 second then ~90mW (0.09 J/...
Sherman's user avatar
  • 81
1 vote
1 answer
230 views

Relaxation Oscillator LED Flashlight

I'm trying to understand the circuit presented in this video: https://youtu.be/qfgX93o8HzY?t=229 We states that when the power is first turned on, the left-most transistor has 0v at it's base so it is ...
Cdevelop's user avatar
  • 307
0 votes
0 answers
164 views

Low voltage (self-oscillating) boost for solar powered pond pump

Long story shortened: I am currently designing a small filter for my pond using a small pump (6V-12V, upto 540mA) with UV-C LEDs parallel to it. Currently, it is battery powered (9V, 6x1.5V AA cells) ...
Evochrome's user avatar
  • 101
2 votes
1 answer
2k views

Simple self-oscillating flyback converter

I am studying switching power supplies, starting from the simple ones. I've just concluded looking at the joule thief and the blocking oscillator, and now I am progressing to self-oscillating flyback ...
Andrew Effiong's user avatar
1 vote
0 answers
343 views

I want to design a joule thief circuit with input of 2mV and output 1.5V

I want to design a joule thief circuit having an input of 2mV and output of 1.5V. I searched for low input joule thief (JT) and I found that by using ALD110800/ALD110900 (they have zero threshold ...
Kashif Naeem's user avatar
0 votes
1 answer
573 views

How do I simulate this unconventional Joule Thief?

Here is a transistor-based simulation of the manually-commutated switched-capacitor SMPS circuit discussed at the bottom of this question, that helps me to think and verify the performance of this ...
MicroservicesOnDDD's user avatar
3 votes
3 answers
2k views

How much energy is stored in a AA battery when its voltage has dropped to 1.2V?

The general question is how useful it is to use weak batteries with a boost converter - say, boosting 3AA of 1V each to 5V? According to this image it seems that only 5% of the energy is left when the ...
OMGsh's user avatar
  • 169
1 vote
1 answer
429 views

What's wrong with joule thief circuit? [closed]

Transistor 2n3904 Homemade transformer with 10 turns Power supply 1.5 v Schematic: I think the toroid winding shorts the power supply as it happens with my buck converter. I think the toroid ...
Jyotir's user avatar
  • 165
1 vote
3 answers
4k views

What is a power factor correction choke (PFC choke) and how does it work?

They Exist This Link at Newark displays "Power Factor Correction Chokes", which I did not know existed. I have a linear motor which I suspect really needs power factor correction. Please tell me ...
MicroservicesOnDDD's user avatar
1 vote
2 answers
202 views

Charging a big capacitor from a weak power supply

Let's say I need to charge a 4m7 (4,700uF) capacitor to 5V, from a 1.5V battery with an internal resistance of 100 ohms. I'm trying to use a typical joule thief with something like soft-start, to ...
user avatar
2 votes
1 answer
228 views

Joule thief modelling

I am trying to use a Joule thief circuit to harvest energy from an almost dead battery, but the references that I found on forums or in conference papers just explain how the Joule thief circuit works,...
Back Link's user avatar
  • 103
5 votes
3 answers
811 views

Mosfet or bjt choice for low voltage joule thief application

I make solar energy harvester using joule thief circuit with a small solar cell as the input. The output voltage from the solar cell is 0,5V. But the generic transistor, exactly silicon material need ...
Back Link's user avatar
  • 103
2 votes
1 answer
758 views

Single Cell LED boost Converter

I am planning on powering 10 white LEDs (LUXEON 3014) from a single AA rechargeable battery with Vin min=0.9V, Vin max=1.4v VLed=2.8v @ 23mA so total Vout for 10 LEDs Vout=28v, iout=23mA I found this ...
Rocky79's user avatar
  • 337
3 votes
2 answers
318 views

Joule thief question

I am basically a rank newbie. The only electrical project I have ever undertaken was to take a light fan and rip it apart and glue magnets in it and with a pair of vise grips spin it around and ...
nite hawk's user avatar
2 votes
2 answers
97 views

Deep Discharge of Cells and Batteries

This is a question related to What makes primary batteries leak on very deep discharge? What are the dangers of deep discharging a cell or battery? I've seen a LiPo battery getting puffy most likely ...
bot47's user avatar
  • 358
-2 votes
5 answers
572 views

Are there any useful applications of weak/dead batteries? [closed]

What are the most recommended circuits and equipment for testing AA and AAA alkaline batteries used in household items? And are there any useful applications of weak batteries which still have a ...
Adrian Machin's user avatar
3 votes
5 answers
2k views

Is a Joule thief a constant current source?

Wikipedia describes a Joule thief, shown below, as a circuit that can be used to provide constant load even when voltage of a battery decreases. At least that's what I think the article means. ...
Tomáš Zato's user avatar
  • 1,064
7 votes
3 answers
11k views

Understanding a Single Transistor Flyback Transformer Driver?

I've been watching a few analyses of CRT flyback transformer drivers and can't understand why the transistor would shut off. To my naive perspective, it appears that the transistor should never shut ...
Sarah Szabo's user avatar
-2 votes
1 answer
650 views

How do I calculate the power consumption when my circuit draws AC and DC current and I only have a cheap DMM? (Joule Thief) [duplicate]

:) So. How do I correctly calculate the power consumption of this circuit? :) I don't have an oscilloscope or an DMM that measures I. My DMM is an Extech EX330, which is quite good for it's price. ...
Distelzombie's user avatar
3 votes
3 answers
709 views

Why does DMM show AC and DC current when source is a battery? (How to calculate power in this case?)

The circuit is an altered Joule Thief of my design that is driven by an AA or AAA battery. I’m observing the current at the battery anode with my DMM in series. (Extech EX330) This circuit is ...
Distelzombie's user avatar
1 vote
1 answer
562 views

Efficiency question of # of LEDs for 6 volt 4 cell Joule Thief Flashlight circuit

This is a high voltage Joule Thief circuit simulation I developed in LTSpice. I am sure that it qualifies as a true Joule Thief because, in the picture below, we are zoomed into the "dead" voltage ...
MicroservicesOnDDD's user avatar
2 votes
2 answers
467 views

The Joule Thief is what kind of oscillator? Armstrong? Relaxation? or what? Thanks!

On Wikipedia, the Joule Thief is described as being an Armstrong oscillator, which I strongly believe it is not (because it has no capacitor). But the Wikipedia article tries to back up this ...
MicroservicesOnDDD's user avatar
4 votes
2 answers
3k views

Understand the Joule Thief circuit

I quote from Wikipedia (https://en.wikipedia.org/wiki/Joule_thief): ... This self-stroking/positive-feedback process almost instantly turns the transistor on as hard as possible (putting it in the ...
KiwiArthur's user avatar
1 vote
4 answers
2k views

Cannot get Joule thief to work

For a few weeks now I've been trying to construct a Joule thief using a schematic commonly found on the web: It consists of an NPN transistor, a 1 kΩ resistor, two coils wound around a ferrite core, ...
Ian's user avatar
  • 13
1 vote
2 answers
802 views

5V UPS circuit with NiMH joule thief backup

I'm trying to design a UPS circuit for microcontroller backup. Require 3.7-5V, and less than 50mA for 10 seconds every 15 min. Power cuts in my area are never longer than 3hours, and occur rarely. I'...
Indraneel's user avatar
  • 2,177
41 votes
7 answers
44k views

Why can't I light a LED with a 1.5 V battery?

The LED I am using requires a higher voltage to light than I have supplied, and as a result, it doesn't light at all. I would expect at least a dim light, but light is not generated. Why this ...
Diego Alves's user avatar
13 votes
4 answers
11k views

A 1USD 11W led bulb circuit and parts analysis

I know this is not a huge deal, but still I want to do it because for Three reasons: 1, it only costs 1 usd. Yep, this is a very cheap led bulb, and I need to take it apart to see if it's trust worthy....
user avatar
2 votes
3 answers
880 views

Joule thief point

I have this circuit from a flashlight that runs an LED with just 2xAA batteries. Initially I thought it used a boost converter or a joule thief but when I opened it up I found that it did not. It ...
Kokachi's user avatar
  • 690
4 votes
1 answer
2k views

Help identifying a transformer with yellow bobbin and clarifying its purpose

I've a small yellow taped transfomer. It has 6 terminals and one of the input and output terminals are shorted. It has a number (14) on one of the sides. I'd like to know the input and output ...
A_k's user avatar
  • 43
3 votes
2 answers
1k views

Joule thief - Why only single celled?

According to this Wikipedia article: It can use nearly all of the energy in a single-cell electric battery, even far below the voltage where other circuits consider the battery fully discharged (or &...
user6262626262's user avatar
1 vote
4 answers
344 views

Boost converter confusion

I have seen many times on the Internet how a boost converter can be used to step up the voltage of a low voltage battery (like 1.5 V) to a higher level to light up an LED which normally wouldn't ...
S. Rotos's user avatar
  • 3,217
2 votes
1 answer
339 views

How calculate inductor discharge time through LED?

UPDATE Overnight I realized I'd been sleeping as I read part of the textbook I've been using or at least didn't quite fully grasp the purpose of inductor volt-second balance. I added the results of ...
scanny's user avatar
  • 7,172
2 votes
1 answer
2k views

How a Joule thief works?

I think this website explains a Joule thief in a wrong way: http://buju357.blogspot.com.eg/2013/06/joule-thief-theory-of-opperation.html The website says: "The increasing collector currentflowing ...
Michael George's user avatar
1 vote
1 answer
2k views

lighting up a led with 30 millivolt-0.1 volt with joule thief?

I want to light up a led with my hand heat by using a peltier cooler. how can I light up a led with 30 millivolt-0.1 volt with a joule thief? Should I connect more transistor in parallel or give more ...
Abtahee Salekeen's user avatar
1 vote
2 answers
709 views

Most efficient way to generate 3-4 volts from less than 0.5 to 1.5 volts

I am looking for a way to convert power from a 1 farad supercapacitor charged by a solar cell into enough voltage to power an LED. The supercapacitor will contain up to 2 volts from the solar cell. I ...
3871968's user avatar
  • 889
2 votes
1 answer
569 views

Running LED on low voltage for a long time

I am trying to run a 0.5W white LED on a 2.4 V supply from a rechargeable battery. The LED needs a voltage drop of 3V to light up. My only constraint is to use commonly available components only. ...
Siddd's user avatar
  • 43
2 votes
5 answers
11k views

White LED W/ 3V or less?

I'm designing a front end bike light just for the fun of it, and I've hit a problem. So far my design will have an input voltage of 3V, but all the white LEDs I find have a forward voltage of 3.2V or ...
Gigaxalus's user avatar
  • 189
18 votes
4 answers
2k views

Is there any benefit to using a voltage booster (such as Batteriser) on "dead" batteries?

The Batteriser [Edit: removed dead, harmful link] is a crowd-funded product intended to extend battery life by boosting the voltage. It is basically a joule thief that is in a tiny package that slips ...
JYelton's user avatar
  • 34.3k
20 votes
2 answers
8k views

Regulated Joule Thief: why it works?

Please explain to me why this circuit can give me a regulated 5 V? I understand the Joule Thief part, but why the regulator part work? simulate this circuit – Schematic created using CircuitLab ...
Maxthon Chan's user avatar
  • 2,873