UCVC

[resonanceman]

Is this just the secondary of the Joulethief?

Jesus

This   circuit is for controlling voltage going to a Ultra cap.
The coil circled in red could  be called a secondary of the JT.
I added this  winding to a JT charger I already had.

I plan on  testing  a way to use this circuit with a JT charger that has no room on the toroid  for another winding.

Soon I will  switch to a schematic that shows  the JT charger and the voltage control circuit.

I wanted to try to keep  it as simple as possible at first........so I only did the voltage control circuit.

gary

[resonanceman]

My goals for this circuit were

Low parts count.
Common parts only.
Charge indicator light , so I can gauge the  approximate charge level at a glance without a meter.

gary

[resonanceman]

A few more details about this circuit.
A relatively large transistor is needed.
I tried a 3904 ........I could  not get it to work.
So far most of my tests have been with a TIP2055
I tried a MOSFET ......couldn't get it working........yet.



I use several meters when  expermenting  with this circuit.
I monitor  the voltage of the primary of my JT charger.
I also monitor my supercap voltage and my charge battery voltage.
I am not currently  trying to feed back to  the JT battery

This circuit may be easier to make using a candy cane  type JT charger.... with the candy cane  coils it is very quick and easy to add the secondary  for this circuit .
The  secondary I am currently  using is pretty much identical to my primary winding on this charger.
Both go through the centers of all the toroids.
I stopped using this kind of secondarys a long time ago because this type of secondary will always take  priority over the other windings....... it is just to powerful to co exist with the normal secondarys.

gary

[nievesoliveras]

Thank you @resonanceman!

You have quite a project there.
The mosfet has to be driven by a small transistor like 2222A or similar.

Jesus

[resonanceman]

Thank you @resonanceman!

You have quite a project there.
The mosfet has to be driven by a small transistor like 2222A or similar.

Jesus

Jeasus

Thanks



So if I understand right  you are saying that the mosfet setup would  have to be kind of like a darlington transistor?
I am still pretty new at building things ......and maybe a little slow.
Can you draw a schematic  of how the transistors would  be  wired?
I think MOSFETS would be ideal .......but  the fact that  they have little or no  current flowing through the base eliminates the LED indicator light.
That is really not a problem  because  the right sized coil added in series with the control  coil could  be used to power a LED whenever  there is  current  flowing through the  control  coil. ( I have done this on a few  charger circuits I have made )

gary