Tulojänniteimpedanssi

Tulojänniteimpedanssi, often referred to as input impedance, is a fundamental concept in electronics, particularly relevant when analyzing circuits and signal transmission. It represents the opposition that a circuit presents to the flow of alternating current (AC) when a voltage is applied to its input terminals. Impedance is a more general term than resistance, as it accounts for both resistance and reactance, which arises from capacitors and inductors within the circuit.

In essence, tulojänniteimpedanssi describes how a circuit "reacts" electrically to an incoming voltage signal. A high input impedance means the circuit draws very little current from the source. This is often desirable, as it prevents the source from being "loaded down," which could alter the signal being transmitted. Conversely, a low input impedance means the circuit draws more current.

The unit of impedance is the ohm (Ω), the same as resistance. It is typically represented as a complex number, where the real part is the resistance and the imaginary part is the reactance. In practical applications, understanding and matching tulojänniteimpedanssi between different circuit stages or between a source and a load is crucial for efficient power transfer and accurate signal reproduction. For example, in audio amplifiers, a high input impedance is important to avoid degrading the signal from the preceding stage.