Joule Thief

[crowclaw]

Hello All...

I made a small joulethief that lights a LED quite ok at only  0.54v @ 0.14 mA.

If someone wants to make a joulethief with a battery (AA) @ 1.5v, what can you put the battery through to have only about .2 to .4v going to the circuit would you put the battery through a high resistor or something ?

@ Free Pow
use a diode(s) in series with your supply. the junction drops 0.7v for silicon and less for schottky types. Better than using a resistor. Kind Regards merv

[freepow]

Thanks for replying.

Is it possible to say... Have a low voltage supply of only  0.2 volts and going through either a Capacitor charge pump to make 0.6v  or  to trick the transistor into starting at 0.2v ?  for a joulethief.

Any one done this... ?

[xee2]

Thanks for replying.

Is it possible to say... Have a low voltage supply of only  0.2 volts and going through either a Capacitor charge pump to make 0.6v  or  to trick the transistor into starting at 0.2v ?  for a joulethief.

Any one done this... ?

For the circuit I posted I actually used a large capacitor in place of the battery and then ran the circuit while monitoring the capacitor voltage as it went down. Note that the output has to be several volts to light an LED.

[the_big_m_in_ok]

Hello All...

I made a small joulethief that lights a LED quite ok at only  0.54v @ 0.14 mA.

Can someone tell me how to convert 1.5v down to say around .2 to .4v   a simple circuit please !

A string of voltage dividers?  Resistors, or maybe diodes?  They're simple.

--Lee

[freepow]

Hello,  Can someone help me with a very simple circuit...

This is what I want it to do...  starting with a 4v solar panel then charging a small super cap up to about 
1.5 ~ 2.0v  with a red LED showing it charging, and when the super cap reaches the desired voltage 1.5 ~ 2.0
then the same red LED light will go out and no more charge will come through !

Is this possible ?