Joule Thief 101

[tinman]

I think I've essentially weighed in on this already with the challenge I posted. The power source was to be a bench supply set to 1.5V. It's the only way to establish a known fixed input condition. The Ro of most bench supplies should be low enough such that 100mW of power draw isn't going to drop the voltage much nor cause ripple on the output.

Poynt

We are not talking about the challenge,we are talking about the two JT circuit's.
While the battery is running a JT circuit(or any load),and the voltage drops across that battery,dose not the internal resistance/impedance of the battery increase?.
If so,then is energy dissipated across this resistance?
If that is also correct,would it not be more efficient to avoid sending current through this resistance as much as possible ?.


Brad

[tinman]

Let's see if Brad can figure that out first, it's his pearl of wisdom.

"'Eye sea,' said the blind man."

I think you have forgotten much of what you have said in this thread MH.
Perhaps you should go back and review the discussion in relation to having a VR on the base,and what you said about it making no difference to light output by decreasing the base resistance,due to the internal resistance/impedance of the battery as the voltage drop's.
This may stop you from dropping your self in it again

Just a suggestion


Brad

[MileHigh]

I think you have forgotten much of what you have said in this thread MH.
Perhaps you should go back and review the discussion in relation to having a VR on the base,and what you said about it making no difference to light output by decreasing the base resistance,due to the internal resistance/impedance of the battery as the voltage drop's.
This may stop you from dropping your self in it again

Just a suggestion

Brad

I can hear the sounds of the frying pans clanking off in the distance.

I tried to repeatedly to explain to you what the base resistor was for you but you would have none of that.  I tried repeatedly to explain to you that your test that showed a limited amount of brightness change in the LED was just a distant secondary effect of changing the value of the base resistor but you wouldn't have any of that.  Just like the YouTube clip explaining how a Joule Thief works got you all confused, frustrated, and mad, you clearly have no understanding about how a Joule Thief works even though it must have been explained to you at least a dozen times.

Here is your big bamboozle moment:

The chances of TK changing the value of the base resistor in the second circuit to bring the Lux output to the same level as the first circuit while maintaining proper Joule Thief circuit operation are essentially nil.

Here is your big bamboozle moment II:

To carry out the test correctly using a cap in place of the battery,you would have to include a series variable  resister,and increase the resistance value to mimic that of the internal resistance value of the battery as the voltage drops.

Okay!  So the supercapcap drops from 1.5 volts to say one volt.  You measure the output impedance of the battery when it also has dropped to one volt driving when the Joule Thief and say for illustrative purposes the output impedance of the battery is measured as being 10 ohms.

Here is where Brad's brain is on fire!

He takes his supercap which is outputting one volt, then adds the series resistor of 10 ohms, and then connects the Joule Thief load.  "We have the technology."

Then he sets the setup off to run, and WHOOPS!, he is not measuring one volt at the Joule Thief now.  He is only measuring 0.85 volts!

What's going on?  Brad says, "I know when my supercap is at one volt I must put a 10-ohm resistor in series.  But then the voltage at the Joule Thief is 0.85 volts."  "I am confused, because I know when my battery voltage is 0.85 volts, the output impedance is 12 ohms and I am supposed to put a 12-ohm resistor in series."

"But I just put a 10-ohm resistor in place but now I have to put a 12-ohm resistor in place??"

The steaming she is a starting, the sizzling sound she is a crackling.  Get your marshmallows out!

The fans from Bizarro World start up a chant, "More discombobulator!  More discombulator!" with the clanking sound of frying pans in the background.

The moral of the story:  Avoid the Logic Discombobulator and think first before you leap into the forum.

[tinman]

I can hear the sounds of the frying pans clanking off in the distance.

I tried to repeatedly to explain to you what the base resistor was for you but you would have none of that.  I tried repeatedly to explain to you that your test that showed a limited amount of brightness change in the LED was just a distant secondary effect of changing the value of the base resistor but you wouldn't have any of that.  Just like the YouTube clip explaining how a Joule Thief works got you all confused, frustrated, and mad, you clearly have no understanding about how a Joule Thief works even though it must have been explained to you at least a dozen times.

Here is your big bamboozle moment:

The chances of TK changing the value of the base resistor in the second circuit to bring the Lux output to the same level as the first circuit while maintaining proper Joule Thief circuit operation are essentially nil.

Here is your big bamboozle moment II:

Okay!  So the supercapcap drops from 1.5 volts to say one volt.  You measure the output impedance of the battery when it also has dropped to one volt driving when the Joule Thief and say for illustrative purposes the output impedance of the battery is measured as being 10 ohms.

Here is where Brad's brain is on fire!

He takes his supercap which is outputting one volt, then adds the series resistor of 10 ohms, and then connects the Joule Thief load.  "We have the technology."

Then he sets the setup off to run, and WHOOPS!, he is not measuring one volt at the Joule Thief now.  He is only measuring 0.85 volts!

What's going on?  Brad says, "I know when my supercap is at one volt I must put a 10-ohm resistor in series.  But then the voltage at the Joule Thief is 0.85 volts."  "I am confused, because I know when my battery voltage is 0.85 volts, the output impedance is 12 ohms and I am supposed to put a 12-ohm resistor in series."

"But I just put a 10-ohm resistor in place but now I have to put a 12-ohm resistor in place??"

The steaming she is a starting, the sizzling sound she is a crackling.  Get your marshmallows out!

The fans from Bizarro World start up a chant, "More discombobulator!  More discombulator!" with the clanking sound of frying pans in the background.

The moral of the story:  Avoid the Logic Discombobulator and think first before you leap into the forum.

Lol
You are a strange man MH.


Brad

[ramset]

Would seem a med imbalance...
the auditory hallucinations should calm down in a day or two..."I can hear the sounds of the frying pans clanking off in the distance.".

Might take longer for the others to stop...["steaming Brain Fires" and such]

I suggest a few days off and  lay off the Old Star trek marathons ...

and definitely no old Pink panther marathons!!

could make the  twitching much worse !!




Oh and back to crayons for the time being no "pens" or other sharp objects.