Amplifiers

For most practical amplifiers, the input and output ranges are pre-defined and are optimised for a particular application. The user does not normally need to concern themselves with the gain calculation, but may need to select the ranges from a row of switches or links.

The dynamic range is the frequency range over which the output can track the input. For slow-changing measurements such as weighing of silos and tanks, using a narrow bandwidth will give benefits in terms of noise and stability. For fast changing (dynamic) measurements such as engine torsional vibrations, then a wide bandwidth (> 1 kHz) is usually required, and short-term stability is less important.

The characteristics of an amplifier are defined in the specifications section of the relevant data sheet and should be compared against the essential requirements of the measurement task. As a general rule, first select the appropriate input and output range, then consider the bandwidth and filtering options, before going on to details such as stability and temperature performance.