Amplification

Amplification is the process of increasing the strength or magnitude of a signal or quantity. In engineering and science, amplification converts a small input into a larger output, typically with the aim of improving detectability, range, or usability while preserving essential information. The gain of an amplifier is the ratio of output to input, commonly expressed as a unitless factor or in decibels.

Electronic amplification uses devices such as transistors or vacuum tubes to provide voltage, current, or power gain. Amplifiers may operate linearly or nonlinearly, and feedback is commonly used to improve stability and reduce distortion.

Optical amplification increases light intensity with devices such as laser amplifiers and erbium-doped fiber amplifiers. Acoustic amplification uses speakers and microphones. In biology, PCR and related methods amplify DNA sequences to increase their quantity.

Key performance factors include gain, bandwidth, input and output impedance, noise, distortion, and dynamic range. In electronics, decibels quantify voltage gain as 20 log10 and power gain as 10 log10. Saturation and compression set output limits.

Applications span communications, audio reproduction, instrumentation, research, and medicine, where amplification enables detection, transmission, or measurement of weak signals.