What is supply and temperature independent biasing?

The signal or output of a circuit is often affected by changes in the supply voltage and/or ambient temperature. A biasing circuit is designed to consistently output a selected voltage (or current). Depending on the circuit topology, a change in supply voltage or temperature can cause the intended value to drift. In an increase in temperature can, for example, increase resistances in a circuit. Such effects are usually undesireable and thus a supply/temperature independent bias would be needed. Electronic component manufactures will frequently provide tolerances for outputs relative to changes in supply voltage and temperature.