Capacitor More Uses

Timing

• R C timing circuits use a resistor and a capacitor for timing purposes.
• The capacitor charges through the resistor.
• A bigger resistor will make the capacitor take longer to charge.
• Also a bigger capacitor will take longer to charge.

Coupling

• A capacitor connecting two subsystems.
• Also known as a DC blocking capacitor.
• Couple an AC signal from one subsystem to the next.
• Prevent DC potentials from being coupled from one subsystem to the next.

Decoupling

• Remove unwanted AC signals from the circuit.
• One capacitor leg is connected to ground and any AC signals are passed straight to ground.

Smoothing

• DC power supplies produce lumpy DC.
• The smoothing capacitor stores enough charge to smooth out the lumps.
• Smoothing capacitors are often very big.
• To improve the smoothing effect, use a bigger capacitor.
• Smoothing is really the same as decoupling. You want to remove the unwanted AC ripple.

Frequency Filtering

• This is an A Level  topic but many GCSE and AS projects might need to take this into consideration.
• Since capacitors pass high frequencies and block low ones and DC, they can be used to filter low or high frequencies.
• Capacitors can be wired up to couple (pass) or decouple (block) higher frequencies.

Tuning

• When combined with an inductor, a tuned circuit is formed.
• This is used in radio tuning to select the wanted signal and reject others.