I'm trying to figure out how I can have a capacitor charge and discharge in a simple circuit automatically and continually. Can somebody help. Thanks.

 

hi,
We need more information about your project.
Capacitors, Voltages, Currents and charge/discharge times etc.

E

 

Its not really a project, I'm just playing around with components and trying to figure stuff out. The circuit is powered by a 9v battery.

I understand the capacitor will charge until it cannot charge anymore and also that it will only discharge when the current removed from it. I am trying to figure out how to achieve this.


Thanks for the reply.

 

thaaaaaaaaaaaaaaanks

 

Its not really a project, I'm just playing around with components and trying to figure stuff out. The circuit is powered by a 9v battery.

I understand the capacitor will charge until it cannot charge anymore and also that it will only discharge when the current removed from it. I am trying to figure out how to achieve this.
Thanks for the reply.

Connect one end a resistor from the +V of the 9V battery and the other end to the +V terminal of the capacitor [assumed polarised capacitor].

Connect the -V of the battery to the -V of the capacitor.

As soon as you complete the connections the capacitor voltage will rise exponentially. A DVM across the capacitor terminal will show this rise.
It will fully charged to close to 9V in 5 Time Constants.

When fully charged, disconnect the battery from the circuit and connect the free end of the resistor to the -V of the capacitor, the cap will discharge thru the resistor,, measure the Vcap with your DVM.

Use this link.
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/capdis.html
E

 

You might like to look up the "Blinky" circuit. It alternates flashing two LEDs and the timing is accomplished by charging and discharging capacitors. Fun and instructive project.

 

Or an NE555 in the astable configuration. It works by alternately charging an discharging a capacitor, and the way it does so would be quite instructive.

Bob

 

Many thanks for the info guys. Will check out the circuits you mention.

 

A simple relaxation oscillator is made from 1 CMOS inverter, 1 Resistor, and 1 Capacitor.

http://mysite.du.edu/~etuttle/electron/elect13.htm
http://en.wikipedia.org/wiki/Schmitt_trigger
http://en.wikipedia.org/wiki/Relaxation_oscillator