Charging and Discharging of two capacitors

In summary, the net charge on two capacitors is the sum of the original charges, but you must keep track of the signs when connecting them. The segments' charges and capacities are negligible compared to capacitors' charges and capacities, and any potential difference between segments is taken care of by a small equalizing electrical transient.
  • #1
Hijaz Aslam
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1
Two capacitors with different capacitance are charged with two different voltages. When we connect both the capacitors with the similar terminals (that is positive terminal of one capacitor to the positive terminal of the other and vice-versa) the net charge is the sum of the former individual charges.

Whereas when we connect both the capacitor (without any battery or cell in the circuit) with the opposite terminals (that is positive terminal of one capacitor connected to the negative of the other and vice-versa) the net charge is taken as the difference of the former individual charges of both the capacitors.

Physically how does this happen?
 
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  • #2
When the terminals are connected together, the net charge is always the sum of the original charges, but you must keep track of the signs. In one case, you are adding positive charges together, Q1+Q2; in the other case, you are adding positive charges to negative charges, so it looks like Q1 + -Q2 = Q1 - Q2.
 
  • #3
Physically how does this happen?

Like charges are cumulative.
Opposite charges cancel each other.
 
  • #4
Alright, so when we connect the capacitors the segment which connects each plates adds up or cancels out according to the connection?
But how does this happen in terms of the electrons which are the basic constituents that contributes to the charge flow?
 
  • #5
Hijaz Aslam said:
Alright, so when we connect the capacitors the segment which connects each plates adds up or cancels out according to the connection?
But how does this happen in terms of the electrons which are the basic constituents that contributes to the charge flow?
The segments' charges and capacities are negligible compared to capacitors' charges and capacities.
If there is a potential difference between segments prior to the series connection of the caps, small equalizing electrical transient takes care of it.
 
  • #6
Hijaz Aslam said:
Alright, so when we connect the capacitors the segment which connects each plates adds up or cancels out according to the connection?
That's right.

Hijaz Aslam said:
But how does this happen in terms of the electrons which are the basic constituents that contributes to the charge flow?
The electrons are free to redistribute themselves until equilibrium is reached.
 
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  • #7
If you have an excess of 2000 electrons (eg a -ve charge) on one bit of metal and an excess of 1000 on another then when you connect them together you have an excess of 2000 + 1000 = 3000 electrons.

If you have an excess of 2000 electrons on a bit of metal and a deficiency of 1000 (eg a +ve charge) on another then when connected you have of 2000 + (-1000) = 1000.
 
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  • #8
CWatters said:
If you have an excess of 2000 electrons (eg a -ve charge) on one bit of metal and an excess of 1000 on another then when you connect them together you have an excess of 2000 + 1000 = 3000 electrons.

If you have an excess of 2000 electrons on a bit of metal and a deficiency of 1000 (eg a +ve charge) on another then when connected you have of 2000 + (-1000) = 1000.

I think that gives a sort of 'quantum explanation' for the problem.
Thanks for your support everyone!
 

1. How does charging and discharging of two capacitors work?

Charging and discharging of two capacitors involves the transfer of electrical charge between the two capacitors through a conductive path, such as a wire or resistor. When connected in series, the capacitors will charge and discharge according to the voltage and capacitance values.

2. What is the difference between charging and discharging of two capacitors?

Charging of two capacitors involves the transfer of electrical charge from a power source to the capacitors, while discharging involves the release of stored charge from the capacitors. In charging, the voltage across the capacitors increases, while in discharging, the voltage decreases.

3. How do the capacitance values affect the charging and discharging of two capacitors?

The capacitance values determine the amount of charge that can be stored on the capacitors and the rate at which the capacitors charge and discharge. Higher capacitance values result in a slower rate of charging and discharging, while lower capacitance values result in a faster rate.

4. What happens to the energy during the charging and discharging of two capacitors?

During charging, energy is transferred from the power source to the capacitors, increasing the electrical potential energy. During discharging, the stored energy in the capacitors is released, and the electrical potential energy decreases.

5. What are some real-world applications of charging and discharging of two capacitors?

The charging and discharging of two capacitors are commonly used in electronic circuits, such as flash cameras and strobe lights. They are also used in energy storage systems, such as backup power supplies and hybrid electric vehicles.

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