Joule Thief 101

[allcanadian]

7. With less electricity going into the base of the transistor, the collector-emitter channel begins to close. This allows less electricity to travel through the second coil.
8. A drop in the amount of electricity in the second coil induces a negative amount of electricity in the first coil. This causes even less electricity to go into the base of the transistor.

Induces a negative amount of electricity in the first coil?, a negative amount of something is less than nothing. Sounds like some kind of woo woo perpetual motion claim to me, has no credibility.
Although according to a scientific study just made up by me 9 out of 10 people under the age of four may believe in negative lectricity.


AC

[Lakes]

Negative Electrickery Generator.

[tinman]

http://makezine.com/projects/joule-thief-battery-charger/

How a Joule Thief works:

This circuit used in this project is a modified "Joule Thief." A Joule Thief is a self-oscillating voltage booster. It takes a steady low voltage signal and converts it into a series of high frequency pulses at a higher voltage. Here is how a basic Joule Thief works, step by step:
    1. Initially the transistor is off.
    2. A small amount of electricity goes through the resistor and the first coil to the base of the transistor. This partially opens up the collector-emitter channel. Electricity is now able to travel through the second coil and through the collector-emitter channel of the transistor.
    3. The increasing amount of electricity through the second coil generates a magnetic field that induces a greater amount of electricity in the first coil.
    4. The induced electricity in the first coil goes into the base of the transistor and opens up the collector-emitter channel even more. This lets even more electricity travel through the second coil and through the collector-emitter channel of the transistor.
    5. Steps 3 and 4 repeat in a feedback loop until the base of the transistor is saturated and the collector-emitter channel is fully open. The electricity traveling through the second coil and through the transistor are now at a maximum. There is a lot of energy built up in the magnetic field of the second coil.
    6. Since the electricity in the second coil is no longer increasing, it stops inducing electricity in the first coil. This causes less electricity to go into the base of the transistor.
    7. With less electricity going into the base of the transistor, the collector-emitter channel begins to close. This allows less electricity to travel through the second coil.
    8. A drop in the amount of electricity in the second coil induces a negative amount of electricity in the first coil. This causes even less electricity to go into the base of the transistor.
    9. Steps 7 and 8 repeat in a feedback loop until there is almost no electricity going through the transistor.
    10. Part of the energy that was stored in the magnetic field of the second coil has drained out. However there is still a lot of energy stored up. This energy needs to go somewhere. This causes the voltage at the output of the coil to spike.
    11. The built up electricity can't go through the transistor, so it has to go through the load (usually an LED). The voltage at the output of the coil builds up until it reaches a voltage where is can go through the load and be dissipated.
    12. The built up energy goes through the load in a big spike. Once the energy is dissipated, the circuit is effectively reset and starts the whole process all over again. In a typical Joule Thief circuit this process happens 50,000 times per second.

What the heck?   No mention of "resonance" anywhere?!  No mention of "LC" or "RLC" anywhere?!

It must be an NWO plot and they want to hide the truth from you.

Wow-what do you know--works the very same as the good old ssg pulse motor circuit.
Remember me trying to explain that to you MH--the cascade effect that takes place when the transistor starts to conduct due to the current generated in the trigger coil by the passing magnet.
The solid state version works exactly the same.

I have told you a number of times now MH,you do not get to define what a JT circuit is--it is !NOT! one circuit,it is a circuit that work on an effect,and results in the near total drain of what would otherwise be a dead battery.

I would suggest that you have another look at how these circuits work,and how the transistor can still switch on when the battery voltage is lower than the minimum required base voltage to switch the transistor on. You assume that the base voltage has to be high enough to switch on the transistor,but that is not correct at all. You either raise the base voltage,or pull the emitter voltage down to a negative voltage-which is what L1 dose in these circuits.

Lets test this theory of yours that the (your) JT circuit is the best at what it dose.
I will use the good old SS SSG circuit,and we'll make a comparison. Then we'll see what is the best JT circuit.


Brad

[sm0ky2]

Okay the analogy is fine.  Using gravity and Mgh is a little bit less intuitive than the analogy I normally think of.

If the mass is horizontal and on a frictionless surface and connected to a spring is the analogy that I prefer.  Then the energy in the moving mass and energy in the displacement of the spring are in perfect quadrature.  Depending on how you view the variables, the mass is the capacitor and the spring is the inductor, or vice-versa.

MileHigh

This is the analog to the LC circuit, using no ferrite in the inductor. (or the permeability of free space, which is negligible in this case.)

adding both gravity, and friction, is analogous to an RLC, with a ferrite core.

if gravity had a "resonant frequency", this spring would be something strange.......

[tinman]

What is a joule thief.

Quote Makezine.com-->A "Joule Thief" is a simple voltage booster circuit. It can increase the voltage of a power source by changing the constant low voltage signal into a series of rapid pulses at a higher voltage.

Quote wikipedia-->A joule thief is a minimalist Armstrong[1] self-oscillating voltage booster that is small, low-cost, and easy to build, typically used for driving light loads.
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 "dead"); hence the name, which suggests the notion that the circuit is stealing energy or "joules" from the source. The term is a pun on the expression "jewel thief": one who steals jewelry or gemstones
Apparently MH thinks some one high jacked wiki,and th explanation is wrong

Quote Rimstar.org-->The joule thief (aka blocking oscillator) is an electronic circuit that allows you to make use of batteries normally considered dead. A battery is often considered "dead" when it can't power a particular device.

Quote lizarum.com-->A Joule thief allows you to boost the voltage of a dying battery.

The list go's on.
So the JT is not one single circuit,but can be many types of circuits that perform the same operation -->and that is to drain the last remaining energy from a nearly depleted battery.

The circuit dose not even require the use of a transistor,and can be achieved in many different ways--as long as we get the LED to light,while draining the remaining energy from the battery.


Brad