Joule Thief

[TinselKoala]

Hi Bill
Sure, to charge a battery properly you've got to supply it with current at the right voltage, not too much, not too little, and you can do things like pulse charge that can stuff more charge into it faster. A capacitor is more like a bucket; you can dump the charge into it really fast if you can supply the necessary current.
I like using small current at high voltage, multiple times, to build up a full charge at a high voltage on the cap, then draw that charge off at a lower voltage, to power whatever device.
And I like air core resonant coils because they don't have core losses and they have the fastest possible risetime response, which means that the induced voltages in the secondary will be higher for a given input current swing to the primary. The drawback to air core coils is the size, though.

[kb24]

Hi everyone, i finally can get my jt running again..  its problem with my toroid winding afterall.. so i try connect my Earth battery with JT to run my fuji circuit.. but its not working.. i have order some supercaps but havent arrive yet.. so hope to get it soon..

so may i know what possibility that my JT couldnt make my fuji working? is it my voltage or current not enough? my earth battery voltage quite high but very low ampere.. will fuji run on low voltage?

[Pirate88179]

Hi everyone, i finally can get my jt running again..  its problem with my toroid winding afterall.. so i try connect my Earth battery with JT to run my fuji circuit.. but its not working.. i have order some supercaps but havent arrive yet.. so hope to get it soon..

so may i know what possibility that my JT couldnt make my fuji working? is it my voltage or current not enough? my earth battery voltage quite high but very low ampere.. will fuji run on low voltage?

I am no expert but, if your eb has exceeded 1.5 volts, which many of us have run the Fuji from, Then my guess would be your mA's are too low, or not flowing enough to keep up with the demand.  So, this is where the b-caps or supercaps come in.  In reality, if you looked at you eb's output on a scope, you might see the same high spikes that I have seen on mine.  These spikes will charge a supercap...and pretty quickly too....then you can use this a real power to drive the Fuji...or whatever you want.

Bill

[dasimpson]

ok this is strange i started a longivity test last night

starting voltage and current draw were

00:00 hours battery 1.27 volt current draw 22.1ma
10:00 hours battery 1.07 volt current draw 20.1ma
11:00 hours battery 0.66 volt current draw 12.2ma
12:00 hours battery 0.56 volt current draw 08.5ma
13:00 hours battery 0.55 volt current draw 08.2ma

the bit i dont undertand is why the current draw changes and why such a huge drop in voltage at 11:00 hours
the lights are still going maybe anogth to read with but i no longer see a ring of light on my celing looks like this circuit i made is also a wash out or well sill start over when my 2n3904 arrive i am trying to use parts that are commen found mainly the line filters in power supplys and other things that tend to run on ac voltage

[dasimpson]

ok think one of my problems might of been the batterys were not fully charged
just found that when they are fully charged they should read 1.4 - 1.45 open reading when fully charged
so ethier my batterys are naffed or 16 hours ant long enoth with my charger