differensforsterker

A differensforsterker, also known as a differential amplifier, is an electronic circuit that amplifies the difference between two input voltages. It takes two input signals, subtracts them, and then amplifies the resulting difference. This type of amplifier is crucial in many electronic applications because it can reject common-mode signals, which are signals that appear identically on both inputs. This common-mode rejection is a key feature that distinguishes it from a standard single-ended amplifier.

The fundamental structure of a differensforsterker typically involves two matched input transistors. The input signals are applied to the emitters or bases of these transistors. The output is usually taken from the collectors, where the amplified difference appears. The degree of amplification is determined by feedback resistors within the circuit.

One of the primary advantages of using a differensforsterker is its ability to minimize noise and interference that affects both input lines equally. This makes it ideal for measuring small signals in the presence of larger, unwanted signals, such as in instrumentation amplifiers, audio amplifiers, and operational amplifiers. The common-mode rejection ratio (CMRR) is a key performance metric for a differensforsterker, indicating how effectively it suppresses common-mode signals. A higher CMRR signifies better performance in rejecting unwanted noise.