Syöttöimpedanssi

Syöttöimpedanssi, or input impedance in English, refers to the impedance seen by a signal source when connected to an input of a device or circuit. It is a measure of how much the input circuit opposes the flow of alternating current. Impedance is a complex quantity that includes both resistance and reactance. It is measured in ohms.

A high input impedance is often desirable because it draws minimal current from the signal source. This ensures that the source's voltage is not significantly loaded down, preserving the signal's integrity. For example, in audio amplifiers, a high input impedance prevents the source (like a guitar or microphone) from sounding muffled or losing its high-frequency content. Conversely, a low input impedance can draw a significant amount of current, potentially altering the signal produced by the source.

In contrast, some applications require a specific or even low input impedance. For instance, in impedance matching, the input impedance of a device is intentionally set to match the output impedance of the source to maximize power transfer. This is crucial in radio frequency (RF) systems and antenna connections. Understanding and controlling syöttöimpedanssi is fundamental to designing and analyzing electronic circuits and systems effectively, ensuring proper signal transfer and performance.