Week 5 Flashcards
Define transistor
A three-terminal circuit component with a non-linear relationship between the applied voltage between pairs of terminals and the device current between those terminals. Arguably the most important component of the digital age
Transistors can act as a digital _____, where the voltage between a pair of terminals controls the flow of current between one of those terminals and the remaining terminal
Switch
What are the two large families of transistors?
Bipolar junction transistors and field-effect transistors
How is a bipolar junction transistor (BJT) constructed?
A BJT is constructed using two pn junctions. It is an asymmetric device and each of the three terminals is different. The doping concentration is highest at one terminal (n++ or p++) and lowest (n or p) at another
What are the three terminals in a BJT?
Emitter, base, and collector
What are the various modes of operation of a BJT?
Cutoff, saturation, active, and reverse-active
True or False: The operating principle of a BJT requires a very narrow base region
True
True or False: The current at the base is proportional to the current at the emitter in active mode
False, it is proportional to the current at the collector in active mode
A BJT is in ______ mode when the EBJ is biased by 0.7 V while the CBJ is reverse-biased
Active
A BJT is in ______ mode when the EBJ is biased by 0.7 V while the CBJ also becomes forward-biased
Saturation
True or False: In saturation mode, there is no longer a fixed relationship between base and collector current, instead we usually assume the collector-emitter voltage is 0.2 V
True
True or False: A BJT in saturation mode has a significantly lower base current than in active mode
False, it is significantly higher
True or False: A BJT in active mode dissipates a significantly larger amount of power than in saturation mode
True
