Applications of Capacitor

Derivation of Capacitor i-v equation in action

The charge Q stored on the plates is proportional to the potential difference V across the two plates. The capacitance C is the proportional constant,...

Voltage Response to Current Pulse

We can rearrange the above equation to calculate voltage if we know current and capacitance....

Before Current Pulse

Before applying the current pulse of 1 mA by closing the switch, there is no current supplied to the capacitor i.e. I = 0 and it does not hold any charges i.e. V0 = 0 and hence the potential difference i.e. voltage across the capacitor is zero. It can be derived mathematically as,...

During Current Pulse

When the current pulse of amplitude 1 mA is applied across the capacitor having capacitance C = 10-6 F for a time duration of 1 ms i.e. T = 10-3 S, I = 10-3 A the initial voltage across the capacitor is zero i.e. V0 = 0 V, voltage across the capacitor during this period can be calculated by following below steps,...

After Current Pulse

Since the switch is closed only for 1 ms i.e. T = 10-3 and opened after the specified time and remains open for E seconds, the amplitude of supplied current drops to zero i.e. I = 0. Since the circuit is not complete, there is no path for the charges stored inside the capacitor to escape and hence the potential difference is maintained inside the capacitor i.e. V0 = 1. Hence voltage across the capacitor is 1 volt. It can be mathematically proven as,...

Charging of a Capacitor

First let us discuss the construction of capacitor. It consists of two metallic plates separated by either air or any other dielectric material such as paper, ceramic, etc. Every material is made up of atoms which consists of positively charged particles called as protons, neutral charged particles called as neutrons, and negatively charged particles called as electrons. Electrons can move around freely inside a conductor whereas the nucleus which consists of protons and neutrons are fixed in their position. A conductor contains equal number of protons and electrons to maintain electric equilibrium....

Discharging of a Capacitor

After the capacitor is charged to it’s rated voltage it remains in that state until an external load is connected which allows to discharge the capacitor....

Energy Storage and Release

The capacitor is an energy storing element which can store a specific amount of energy and release it whenever required. This phenomena is quite important. It is used in various applications mentioned below. It must be noted that a capacitor can slowly discharge itself even if it is not connected to a load....

Applications of Capacitor

Filters: Capacitors are used to create active as well as passive filters. Filters are electronic circuits which allows to pass a specific band of frequency and attenuates all other frequencies. It is connected in series with a resistor for high pass filter and is connected in parallel with a resistor for low pass filter.Rectifiers: A rectifier is a circuit which converts bi-directional AC signal to a constant voltage. A diode circuit is used for rectification however there are still ripples present in the output of this circuit. Hence a capacitor can be connected to suppress this ripples and provide constant voltage.Timing Circuits: A capacitor can be used to provide delay by varying the time constant. It is used along with timer ICs such as NE 555, in monostable mode and a stable mode to vary the width of the generated rectangular pulse.Couplers: Since a capacitor only allows AC signal to flow and cancel out any DC component present in the signal, it is connected in series between the signal source and amplifier block and this capacitors are called as coupling capacitors.Oscillators: A capacitor can be used along with an inductor to create a simple oscillator circuit popularly called as LC oscillator which produces sinusoidal waves due to their spring like behaviour....

Conclusion

In this article we studied that a capacitor is a passive electronic component that can store energy and release it quickly when required. We can conclude that this article answered several questions like what is a capacitor and how does it works as a energy storing device, derived two equations which defines the relation between voltage and current and saw some of its applications....

Capacitor i-v Equation in Action – FAQs

What are passive devices?...