Second Stage Joule Thief Circuits

[Groundloop]

All,

Today I have started to test this circuit.

The circuit works. I use a 10.000uF electrolytic capacitor for
the test. The capacitor charges up and when reached a preset
voltage, discharges through the hexfet transistor and into
my load.

I have not tested the battery feed back yet because I do not have
the 3,6 Volt zener.

More testing is needed before this circuit can be used in a JT setup.

There is one more issue I need to solve. Sometimes the TIC106 stays on
because the current through the relay is just high enough to keep the SCR
on even if the voltage in the cap has fallen to 0,74 Volt. Trying to solve
that problem now.

I could not modify the drawing on one page back so I added the newest circuit here.

[EDIT-1] OK, the circuit as posted here does work. But the discharge voltage threshold is 10,7 Volt.
             So, I need to get that threshold down to 5,1 volt. Working on that now.

[EDIT-2] Can't get the threshold right. The mosfet needs a higher than 5 volt to fully switch on.
             Will not work with the JT as it is now. I need to take a break and rethink this circuit.

Alex.

[mscoffman]

All,

There is one more issue I need to solve. Sometimes the TIC106 stays on
because the current through the relay is just high enough to keep the SCR
on even if the voltage in the cap has fallen to 0,74 Volt. Trying to solve
that problem now.


Alex.

Sometimes one can make use of a transistor switch that can support
a current flow when it is on but not switch that total current flow. When
the current gets low then switch the transistor entirely off then on
again to help out the SCR to switch off.

:S:MarkSCoffman

[Groundloop]

@mscoffman,

Thanks for the tip.

The total current flow through the SCR and the relay is low.
The BS170 can handle the current.

Groundloop.

[guruji]

All,

Today I have started to test this circuit.

The circuit works. I use a 10.000uF electrolytic capacitor for
the test. The capacitor charges up and when reached a preset
voltage, discharges through the hexfet transistor and into
my load.

I have not tested the battery feed back yet because I do not have
the 3,6 Volt zener.

More testing is needed before this circuit can be used in a JT setup.

There is one more issue I need to solve. Sometimes the TIC106 stays on
because the current through the relay is just high enough to keep the SCR
on even if the voltage in the cap has fallen to 0,74 Volt. Trying to solve
that problem now.

I could not modify the drawing on one page back so I added the newest circuit here.

[EDIT-1] OK, the circuit as posted here does work. But the discharge voltage threshold is 10,7 Volt.
             So, I need to get that threshold down to 5,1 volt. Working on that now.

[EDIT-2] Can't get the threshold right. The mosfet needs a higher than 5 volt to fully switch on.
             Will not work with the JT as it is now. I need to take a break and rethink this circuit.

Alex.

Hi Groundloop thanks for the schematic. What are you trying to achieve by this circuit more amps?
And how much are you aiming? Would it be possible that one use small caps to light a heater as gadgetmall did?
Thanks

[Groundloop]

@guruji,

I'm trying to build a circuit that will discharge a big battery capacitor to a load when the
capacitor has reached a preset voltage level. The circuit should also feed back some power
from the battcap to the input AA battery.

Alex.