table of Contents
BJT needs to work in an enlarged state
1. Common emitter amplifier circuit
(1) General
The role of each element
- V B B V_{BB} VB B: Ensure that the launch junction is positively biased.
- R b R_b Rb: Limit the current to prevent the firing junction from burning out.
- V C C V_{CC} VCC: Ensure that the collector is reverse biased.
- R C R_C RC: Make the output alternating voltage.
(2) Direct coupling
Coupling: The transfer of signals between circuits.
(3) Resistance-capacitance coupling
2. Common collector amplifier circuit
3. Common base amplifier circuit
Communication channel
DC path