Capacitors

• ​Shown is a circuit with a capacitor, resistor, and battery

• Initially capacitor is uncharged

• when battery connected current flows to charge capacitor

• As the charge builds up, there is increased resistance because of the repulsion of the charges on the parallel plates

• When capacitor is fully charged, no current will flow.

  • ​Current no longer flows because the parallel plates aren't connected and can't accept anymore charge.

Formulas: Loop Rule

Formulas: Charging a Capcitor

Formulas: Discharging a Capacitor

Capacitor Applications

• Camera flashes work by charging a capacitor with a battery

  • Usually has a large time constant because batteries cannot produce charge very fast

• The capacitor is then discharged through the flashbulb circuit with a short time constant​