Capacitor Charging Circuit - Help Wanted

[john_g]

Hi

Can anyone help me with a circuit? What I am trying to do is fill a capacitor by using the spike output from a bifilar coil (charging circuit) . What I would like to do once the capacitor is full, say 300 Volts, is then switch the charging circuit off. When the capacitor voltage falls below say 250 volts the charging circuit starts up, refilling the capacitor etc, thus the cap is kept essentially fully charged.

Any help/ideas on this much appreciated.

Regards

John

[gyula]

Hi John

Here is a patent from Jean-Michel Cour, in which a voltage comparator 'watches' the voltage level in a puffer capacitor and fires a switch when the voltage level reaches a needed value, seems like your circuit...

espacenet - Original document

You can surely figure out how to change the voltage dividers for your needs.

Gyula

[dragon]

Maybe a simple voltage regulator?

[Guest]

I've been looking up this kind of switching lately, dependant
on voltage. The method I've found uses a circuit called the
Schmitt trigger, through which an operational amplifier is
configured to supply an on and off signal.

The level of voltage you've indicated may be sent through a voltage
splitter using two resistors, tapped in between to obtain a useable
value. This may be the input to the switching circuit...

[ Information - The Schmitt Trigger ]

[ Circuit Calculator ]

[wayne.ct]

Op amps are the answer

Read up on "op amps" and you will get the information you need. Adjust your voltage divider resistors to get the effect you want.

[john_g]

Thanks for replys

Gyula, Dragon, Geotron and Wayne.ct

Many thanks for all the suggestions/directions. Looks like these will do the job so a bit of reading required by me to get up to speed.

Thanks

Regards

John