A characteristic of each pn junction is the negative temperature coefficient of the forward bias. For silicon diodes, it amounts to approximately -2 mV/K and is constant over a wide temperature range. This temperature coefficient has the consequence that semiconductor circuits are always temperature sensitive. This causes problems particularly with analog high-precision circuits (AD converters, reference elements, and so on), which must be circumvented using technical circuiting tricks. The advantage of the temperature coefficient however is that a diode can also be used as a temperature sensor.