Charging and Discharging

Charging and Discharging

1. Charging

   • You charge a capacitor by connecting it to a battery
   • When a capacitor is connected to a battery current flows until it is fully charged.
   • • Same graph for Potential difference (V), Current (I) and Charge (Q)

2. Discharging

   • The discharging of a capcitor is basically using the capacitor a a battery source.
   • When a charged capacitor is connected across a resistor, the current flows in the opposite direction from the charging current. When a capacitor is fully discharged the p.d and the current both equal zero
     • Q=Q₀e^(-t/RC)
     • V=V₀e^(-t/RC)
     • I=I₀e^(-t/RC)

3. Time constant

   • The time constant is the time taken to charge the capacitor through a resistor.
     • 63% of its charging charge
     • 37% of it discharging charge (Q₀)
   • T= CR
     • Larger the resistor longer it takes to charge or discharge
     • Usually the time taken for a capacitor to charge or discharge is 5CR

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