Condensadors

Condensadors, commonly known as capacitors in English, are passive electronic components that store energy in an electric field. They consist of two conducting plates separated by a dielectric. When a voltage is applied, charge accumulates on the plates, creating a capacitance C that relates charge Q to voltage V (C = Q/V). Capacitance is measured in farads, with practical values expressed in microfarads, nanofarads, or picofarads.

Capacitors come in a variety of dielectric materials. Ceramic, plastic film, and mica types are usually non-polar and suitable for signal coupling and high-frequency filtering. Electrolytic capacitors (aluminum and tantalum) provide large capacitance in a compact form but are polarized and have higher leakage and poorer stability. The dielectric material determines voltage rating, temperature coefficient, and tolerance.

Physical construction and parameters affect performance. The basic formula for parallel-plate types is C = ε_r ε_0 A / d, where ε_r is the relative permittivity, A the plate area, and d the separation. Real capacitors have parasitic elements such as equivalent series resistance (ESR) and inductance (ESL) and leakage current. Typical specifications include rated voltage, tolerance, and temperature coefficient.

Common applications include energy storage for power supplies, decoupling and filtering of noise, and timing or coupling in circuits. They are found in almost all electronic devices, from consumer electronics to industrial systems. The earliest devices were Leyden jars in the 18th century; the term condenser was historically used, and the modern term capacitor is standard today.