Joule Thief 101

[MileHigh]

And how could you have possibly seen the LED change in brightness when it was under the light meters sensor?

There is enough going on in that clip to confirm what I said.  What about you?  You were there, just be honest and lay your cards on the table?  Did you see a noticeable increase in the brightness of the LED or not?  If you saw a noticeable brightness increase, how much?  Just a very tiny amount?  A tiny amount?  A bit more than tiny?

Lay your cards on the table.  Did the "brightness control" meet you expectations or not?  Or was it more like you saw the digits change on the light meter but changing the base resistor in your latest clip didn't really work like you expected?

[tinman]

 author=picowatt link=topic=8341.msg478241#msg478241 date=1458786487]
Tinman,

A better way would have been to keep all scope grounds on the battery minus and use both scope channels and probes to measure both ends of the 10R base resistor.  With both scope channel vertical gains set identically (ca 20mv/div) invert one channel and then add them together (or use a math function to subtract one channel from the other).  This allows you to make a differential measurement across the 10R with minimal capacitive loading (particularly if you use 10X probes).


PW

Ok,the results of the test above.
first up,there is no way that we can use 20mV/div--just way to low,so i have used 5v/div
Second--why invert one channel?,as if we keep both channels non inverted,then we just subtract the lowest value from the highest value to get our voltage drop across the 10ohm resistor--but anyway,done as you asked.

Circuit below with scope placement.
I have a wheel that has a selection of set resistance values which i have used for these test.
The first scope shot is with a 1Kohm resistance value(+ the 10 of course).
The second scope shot is with a base resistance value of 820ohms-just the next value down.
The third scope shot is with a base resistance of 550ohms-next value down.

[tinman]

Go ahead and do a timing diagram and demonstrate how the magnetic energy in the core increases when you have current flowing through L2.  Show how this supposedly makes the LED brighter.  Don't just rattle off a spur-of-the-moment "explanation" - roll up your shirtsleeves, pick up a pencil, draw out a timing diagram and try to prove that you are right.

Here is an idea.
How about you put together a JT yourself,and draw your own timing diagrams,and carry out your own testing.
Wouldnt that be a hoot.

[MileHigh]

Here is an idea.
How about you put together a JT yourself,and draw your own timing diagrams,and carry out your own testing.
Wouldnt that be a hoot.

It's not going to happen and you are making the claim and three people have already told you that you are wrong.  So give it a go and try to prove that you are correct.

[tinman]

There is enough going on in that clip to confirm what I said.  What about you?  You were there, just be honest and lay your cards on the table?  Did you see a noticeable increase in the brightness of the LED or not?  If you saw a noticeable brightness increase, how much?  Just a very tiny amount?  A tiny amount?  A bit more than tiny?

Lay your cards on the table.  Did the "brightness control" meet you expectations or not?  Or was it more like you saw the digits change on the light meter but changing the base resistor in your latest clip didn't really work like you expected?

See-your doing it again--changing things to suit your needs.
You know very well that the idea behind adjusting the base resistance as the voltage in the battery drop's,was to maintain the highest amount of light output as possible.
I have proven beyond doubt that this happens,and your theory about V/R limit's-and all other associated garbage was quickly dismissed.

Now you have started on these wakadoo claims about my JT running to fast(frequency to high),and mine is operating differently to Mag's JT--!!!wow!!!
Then there is this giant killer spike,which in actual fact only has a voltage value of 100mV--yes,100mV-->so massive ,not to mention that the time period for this !!!massive!!! spike is that small it's not funny. And then have you dismiss the emitter/base junction capacitance as being the body that could indeed produce this very brief spike of current,is more than comical.

You are doing nothing more than trying your best to backpeddle from further mistakes on your behalf--you do this all the time--try to change the direction of the subject at hand,to turn attention away from your mistakes.

It's not working for you MH.

Decreasing the base resistance as the battery voltage drop's,dose indeed increase the brightness of the LED--proven.
Decreasing the base resistance dose increase the current flowing through L2--proven
Increasing the current through L2 dose increase the magnetic field strength--proven by the fact that the LED gets brighter.

Everything i stated has been proven.
Sorry MH,but you lost another one.

Brad