lähtöresistanssin

Lähtöresistanssi, known in English as output resistance or output impedance, is a fundamental parameter in electronics that describes the internal resistance of a voltage source or the resistance seen looking back into the output terminals of an amplifier or other active circuit. It is a measure of how much the output voltage of a source will change in response to a change in the load current.

For an ideal voltage source, the lähtöresistanssi is zero, meaning the output voltage remains constant regardless of the current drawn by the load. However, real-world voltage sources, such as batteries or power supplies, have a non-zero lähtöresistanssi. This causes the output voltage to drop as more current is drawn. Similarly, amplifiers have a lähtöresistanssi that influences how their output voltage interacts with subsequent stages or loads.

A low lähtöresistanssi is generally desirable for voltage sources and amplifiers, as it leads to a more stable output voltage under varying load conditions. Conversely, a high lähtöresistanssi can result in significant voltage drops and signal attenuation. The concept of lähtöresistanssi is closely related to Thévenin's theorem, which states that any linear electrical network can be reduced to a single voltage source in series with a single resistance, where that resistance is the Thévenin equivalent resistance, equivalent to the lähtöresistanssi.