capacitive

Capacitive refers to properties, devices, or phenomena that involve capacitance, the ability to store energy in an electric field between conductive elements separated by a dielectric. The capacitance C quantifies how much charge Q a given voltage V can store, via C = Q/V. The unit is the farad, with practical components often ranging from microfarads to picofarads.

In circuit theory, capacitors pass alternating current while opposing direct current, a behavior described by capacitive reactance Xc = 1/(2πfC). At DC, a capacitor charges up to the supply voltage and then acts as an open circuit. The energy stored in a capacitor is E = 1/2 C V^2, reflecting the energy stored in the electric field between the plates.

Capacitive components serve many roles in electronics. They store and release energy, filter signals, and smooth power supplies. They are used for signal coupling and for timing in RC networks. Capacitive sensing exploits changes in capacitance to detect proximity or touch, and is widely employed in touch screens, near-field sensors, and buttons. Sensing methods include self-capacitance and mutual-capacitance approaches.

Real capacitors exhibit non-ideal behaviors. Leakage current, equivalent series resistance (ESR), and equivalent series inductance (ESL) affect performance, especially at high frequencies or voltages. The dielectric material determines voltage rating, temperature stability, and aging characteristics. Designers select among dielectric types and form factors to balance capacitance, tolerance, voltage rating, size, and cost.

Capacitive concepts underpin a broad range of electronics, from simple discrete capacitors to integrated sensing arrays, enabling energy storage, filtering, timing, and capacitive sensing across many applications.