Omfangsskifter

Omfangsskifter are components in measurement instruments that allow the user to select among different input ranges. They enable an instrument to handle signals spanning a wide dynamic range while preserving resolution and protecting the device from overload.

In analog instruments, omfangsskifter were typically mechanical rotary switches connected to a resistor ladder that scales the input signal to the internal processing range. In modern digital devices, range switching often occurs automatically (auto-ranging) via the internal analog-to-digital converter and processing software, though manual ranges are still provided on many instruments.

Common applications include handheld and benchtop multimeters, oscilloscopes, power meters, and other sensors or test equipment. The function of a range switch is to reconfigure the signal path, either by changing gain, adjusting attenuation, or selecting different resistive dividers, so that the signal stays within the optimum measurement band of the instrument. This improves measurement accuracy and protects sensitive circuitry from being exposed to excessive signal levels.

Historically, omfangsskifter reflect the evolution from purely analog meters with discrete range options to sophisticated digital and auto-ranging instruments. The term is used in Danish technical literature, with English equivalents often rendered as range switch or range selector.

See also: range selector, selector switch, gain, auto-ranging, resistor ladder.