2. Polarization of active components

All the circuits studied in this text are analog circuits. Biasing active components will therefore always pose the same kind of problems, and a number of typical solutions can be reviewed. The configurations adopted for biasing transistors can be implemented for any other active device, such as varactors, cold FETs, etc. A special paragraph is devoted to this activity, as the inductors, lines and capacitors that must be added to circuits in this way will generally considerably increase the surface area of the circuit, and therefore its cost. In most cases, therefore, particular care must be taken in selecting and arranging these bias circuits.

• Basic polarization diagram

  Figure 18 shows the basic diagram for biasing...