Capacitors
Electronic components that store and release electrical charge, consisting of two conductors separated by an insulating material called a dielectric.
Capacitors
Capacitors are fundamental passive components in electronics that store electrical energy in an electric field between two conductive plates. Their ability to accumulate and discharge electrical charge makes them essential building blocks in modern electronic devices.
Basic Structure
A capacitor consists of:
- Two conductive plates (typically metal)
- A dielectric material between the plates
- Terminals for connecting to circuits
Working Principle
When voltage is applied across a capacitor, electrons accumulate on one plate while being depleted from the other, creating an electric field across the dielectric. This separation of charge stores electrical potential energy, similar to how a spring stores mechanical energy when compressed.
Types of Capacitors
Fixed Capacitors
- Ceramic capacitors
- electrolytic capacitors
- Film capacitors
- Tantalum capacitors
Variable Capacitors
- Air-gap tuning capacitors
- varactors
Applications
Capacitors serve numerous functions in electronic circuits:
-
Power Supply Filtering
- Smoothing rectified current
- Reducing voltage ripple
-
Coupling and Decoupling
- Blocking DC while passing AC signals
- Reducing noise in power supplies
-
Timing Circuits
-
Energy Storage
- Backup power systems
- Flash photography
- supercapacitors
Characteristics
Key parameters include:
- Capacitance (measured in Farads)
- Voltage rating
- impedance
- Temperature coefficient
- Leakage current
Common Issues
- Dielectric breakdown
- ESR (Equivalent Series Resistance)
- Aging effects
- Temperature sensitivity
Modern Developments
Recent advances include:
- Miniaturization for integrated circuits
- Enhanced energy density
- Improved reliability
- Novel dielectric materials
Safety Considerations
Capacitors can retain charge even when disconnected from power sources, making proper discharge procedures essential for safe handling. This is particularly important with high-voltage capacitors used in power supplies and power electronics.