How current relates to capacitance

In summary, adding additional resistors in series to a circuit with a battery, resistor, and capacitor will result in a longer charging time due to the decrease in overall current caused by the increased resistance. This can be mathematically explained by the time constant (RC) which represents the time for the current to decrease to 1/e of its initial value. Therefore, increasing the resistance (R) will result in a longer time constant and a longer charging time for the capacitor.
  • #1
JFS321
75
6
Hi all,

I have a simple circuit with a battery, resistor, and finally, the capacitor.

Am I correct in saying that adding additional resistors will increase the charging time, because adding resistors will decrease the overall current?

Thanks--
 
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  • #2
Basically...yes...with the information you have provided!

PS...unless you connect the resistors in parallel
 
  • #3
JFS321 said:
Hi all,

I have a simple circuit with a battery, resistor, and finally, the capacitor.

Am I correct in saying that adding additional resistors will increase the charging time, because adding resistors will decrease the overall current?

Thanks--
It is really far more fruitful to describe what happens using Maths.
We assume the three are in series. The time constant (time for the voltage across the Resistor to go to 1/e of any initial value) is given by RC. It's an Exponential variation. As the Voltage decreases exponentially, so does the current flowing because I = V/R.
 
  • #4
A more direct way for you to consider the time constant is that RC is the time taken for the CURRENT in the series circuit to decrease to 1/e of its initial value.
(your question related to the current)
T = RC so larger R means longer time for the current to decrease.
Increasing R decreases the current which increases the time to charge the capacitor.
 
Last edited:
  • #5


Hello,

Yes, you are correct in saying that adding additional resistors will increase the charging time of a capacitor. This is because resistance and capacitance are inversely proportional to each other. As resistance increases, the current decreases, and therefore, the rate at which the capacitor can charge also decreases. This relationship can be mathematically represented by the equation Q=CV, where Q is the charge on the capacitor, C is the capacitance, and V is the voltage. As you can see, if resistance increases, the voltage stays the same, but the capacitance decreases, resulting in a longer charging time.
 

Related to How current relates to capacitance

1. What is capacitance?

Capacitance is the ability of a material or system to store an electric charge. It is measured in farads (F).

2. How does current relate to capacitance?

Current and capacitance are directly related. A higher current will result in a larger capacitance, while a lower current will result in a smaller capacitance.

3. How does capacitance affect the flow of current?

Capacitance acts as a barrier to the flow of current. The higher the capacitance, the more difficult it is for current to pass through the material or system.

4. Can capacitance be changed?

Yes, capacitance can be changed by altering the material or system's geometry, the dielectric material used, or the distance between the plates of a capacitor. It can also be changed by changing the voltage applied.

5. How is capacitance measured?

Capacitance is typically measured using a capacitance meter or by using the formula C = Q/V, where C is capacitance, Q is charge, and V is voltage.

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