Contents
Do capacitors discharge exponentially?
The decay of charge in a capacitor is similar to the decay of a radioactive nuclide. It is exponential decay. The decay curve against time is called an exponential decay. The voltage, current, and charge all decay exponentially during the capacitor discharge.
What affects the rate of capacitor discharge?
The rate at which a capacitor charges or discharges will depend on the resistance of the circuit. The other factor which affects the rate of charge is the capacitance of the capacitor. A higher capacitance means that more charge can be stored, it will take longer for all this charge to flow to the capacitor.
Which is the correct equation for the discharge of a capacitor?
The time constant we have used above can be used to make the equations we need for the discharge of a capacitor. A general equation for exponential decay is: For the equation of capacitor discharge, we put in the time constant, and then substitute x for Q, V or I: Where: is charge/pd/current at time t.
How to plot charging and discharging of capacitors?
We can plot an exponential graph of charging and discharging a capacitor, as shown before. However, by manipulating the equation for discharging, we can produce a straight line graph: An experiment can be carried out to investigate how the potential difference and current change as capacitors charge and discharge.
How does the charge of a capacitor decrease?
The discharge of a capacitor is exponential, the rate at which charge decreases is proportional to the amount of charge which is left. Like with radioactive decay and half life, the time constant will be the same for any point on the graph: Each time the charge on the capacitor is reduced by 37%, it takes the same amount of time.
How is the time constant of a capacitor determined?
The time constant is the time it takes for the charge on a capacitor to decrease to (about 37%). The two factors which affect the rate at which charge flows are resistance and capacitance. This means that the following equation can be used to find the time constant: Where is the time constant, is capacitance and is resistance