Joule Thief 101

[tinman]

Do you see why?

Yes
As stated by Mag's and myself many times in the past,you do not get current flowing into the battery in the wrong direction,as the current loop now excludes the battery.
This is shown very clearly with the scope.
I am putting together a test circuit,where i can switch LED positions on the fly,and show the very clear current trace from the P/in(battery).
Should have it altogether by tomorrow.

This is why most do not use what MH calls the standard JT circuit. In fact,the most common circuit used as a JT is the second JT circuit,where the LED is across L2.

This so called !death spike! MH is talking about is very common in a lot of circuit's. Even the good old SSG pulse motor has it,but the back spike in them is far larger than the JTs we have been testing here. So it's not an anomaly(this death spike) ,it is quite normal in many circuit's.

Brad

[MileHigh]

Brad:

It is not a death spike at all.
It is in fact present in all JT circuit's--it's just that no one has taken any notice of it as of yet.
I have now tested 3 different JT circuit's,and it is present in all of them.
This !so called! death spike actually helps in raise the brightness of the LED.

More wilful ignorance and wilful stupidity on display for all to see.  The Joule Thief circuits that you have built and tested are all not working properly.  You have too many turns on the L2 feedback coil and that's causing a breakdown in the transistor junction.  The moral of the story is that if you don't build a "canned version" of a Joule Thief just like beginners are told to build their first SSG without any modifications, then you have to know what you are doing and test it yourself to ensure that it is operating properly.

But since "Brad can't be wrong" you are following through with your insane line of reasoning.  It's a farce.

The death spike does NOT help in the brightness of the LED - it kills some of the energy stored in the magnetic core - and you were told precisely why that is the case.  You must be daft.

You may do what you please MH,but as you only made this !death spike! discovery (that you didnt know existed until i showed some test results),it is clear that you do not really know all that is going on within the circuit.

Big Brother wants you.

Im not going down this babying road with you MH. If you cannot work out where the current flow continues from where the marked dot's are,then you clearly do not belong here.

More "Brad can't be wrong" insanity.  Follow the "red dot" current flow and find yourself at a dead end for lazy babies that are too daft to think through their own statements to completion.  Go for it and show us all where the red dots lead.  Are you the one that belongs here after six years and doing something as foolish and stupid as your "red dot current to nowhere - fill in the blanks yourself" nonsense?

MileHigh

[MileHigh]

Brad:

Partly correct,but only while the battery is still reasonably healthy. As the battery voltage reduces to around .8 volts(in my test setup),the secondary effect is from the current flow in L2.
As battery voltage drop's,the frequency rises,but as we reduce the base resistance,that frequency can be reduced,and the light output maintained--even though the P/in is now less.

Current flow in L2 reduces the magnetic energy stored in the core.  But you "can't be wrong" so just stick to your story to the bitter end.  Brad, the "Pope of Joule Thieves."

What it is looking like is that a reduced base resistance from 1k to 500 ohms does not change the transistor switching properties and therefore you are wasting battery power with a 500-ohm base resistor.  A secondary effect is that the transistor ON time gets longer and the LED gets marginally brighter.

One can speculate with reasonable confidence that if you kept a 1k base resistance and increased the number of turns in L1 then you would get a longer transistor ON time and therefore a brighter LED with a more efficient Joule Thief design.  Of course you still want to fix the error in the circuit first.

My JT is functioning correctly. It functions the very same way the other two i constructed-with only very minor differences due to things like number of turns of each coil,and the size of the toroid core.
All three have the very same operational  characteristics,and near identical scope traces.

Then they are all defective with crippled efficiency and you need to fix the problem like I already stated.

There is no problem with the way the circuit is operating,nor the other ones i built today.
In fact,i will be presenting a JT circuit that is most efficient based around this !now found! reverse current flow.

Welcome to Planet Bizarro where when your device has an internal short-circuit because of a semiconductor junction breakdown, this fact is to be celebrated.

Sorry, but I was sarcastic indeed because of the upside-down dream world you are living in to "protect the Pope."

MileHigh

[tinman]

I will now be continuing my work and experiments on the thread below--where the garbage can be filtered out.
No point in arguing any more with some one that dose not even have a JT to experiment with,nor has any plans to do so--but still remains a self acclaimed ex-spurt in the subject.

I will also be putting the cool joule circuit back together,and having another look at that,and the effects of miller capacitance,where the circuit !can! operate using this effect.This will be done in the thread linked below.

http://overunity.com/16486/resonance-circuits-and-resonance-systems/new/#new


Brad

[minnie]

   Well MileHigh,you have had a good dose of the Tinman!
             John.