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Impedance

maker

Impedance is the measure of opposition that a circuit presents to a current when a voltage is applied.

expanded

In electrical circuits, impedance combines the effects of resistance, inductance, and capacitance. It is crucial in determining how much current flows in a given circuit for a particular voltage and is measured in ohms (Ω). Understanding impedance is essential for designing and analyzing systems such as audio equipment, where impedance matching is critical to optimize performance and minimize signal loss.

examples

An audio amplifier with an output impedance of 4 ohms matched to speakers with an impedance of 4 ohms.

This configuration is commonly used in home audio systems to ensure efficient power transfer and optimal sound quality.

A radio frequency (RF) circuit designed with a characteristic impedance of 50 ohms.

This is typical in RF transmission lines for telecommunications to minimize signal reflection and maximize power delivery.

related terms

Resistance
The opposition to the flow of electric current, typically measured in ohms (Ω).
Resistor
A resistor is a passive electrical component that implements electrical resistance as a circuit element.
Inductance
Inductance is the property of an electrical conductor by which a change in current generates an electromotive force (EMF) in the conductor itself and in any nearby conductors due to electromagnetic induction.
Inductor
An inductor is a passive electronic component that stores energy in a magnetic field when electrical current flows through it.
Capacitance
Capacitance is the ability of a system to store electric charge per unit voltage, measured in farads (F).