Understanding Bias in Semiconductor Devices

[cubejunkies]

Is there not a difference between bias as in "A diode is forward/reverse biased" and establishing the terminal voltages/currents needed to bring say a transistor to the quiescent point?

Just curious

 

[CWatters]

Not really. Bias basically means offset. Just about every semiconductor needs some sort of DC offset to be applied to the input signal to get the device to work as intended.

For example diodes don't switch from conducting to non conducting at 0V there is an offset of 0.7v typically. Likewise transistors only act as linear amplifiers over part of the possible range of voltages that could be applied to them. That range isn't typically centered on 0V, there normally has to be a DC offset or bias.