# Charging/Discharging Capacitors

Discussion in 'The Projects Forum' started by 8-bit, Feb 21, 2014.

1. ### 8-bit Thread Starter New Member

Jan 7, 2014
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0
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.

2. ### ericgibbs AAC Fanatic!

Jan 29, 2010
2,595
393
hi,
Capacitors, Voltages, Currents and charge/discharge times etc.

E

3. ### 8-bit Thread Starter New Member

Jan 7, 2014
27
0
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.

Last edited: Feb 21, 2014

Feb 21, 2014
1
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thaaaaaaaaaaaaaaanks

5. ### ericgibbs AAC Fanatic!

Jan 29, 2010
2,595
393
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.

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

6. ### wayneh Expert

Sep 9, 2010
12,382
3,241
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.

8-bit likes this.
7. ### BobTPH Active Member

Jun 5, 2013
806
121
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

8. ### 8-bit Thread Starter New Member

Jan 7, 2014
27
0
Many thanks for the info guys. Will check out the circuits you mention.

9. ### Papabravo Expert

Feb 24, 2006
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