Lecture 7 Flashcards
What are the main components of a DC power supply?
Transformers, rectifiers, filter, voltage regulator.
What is the purpose of rectifiers in a power supply?
To convert bidirectional AC voltage into unidirectional voltage.
What are the two types of rectifiers?
Half-wave rectifiers and full-wave rectifiers.
What distinguishes semiconductors from conductors and insulators?
Semiconductors require a small amount of energy for electrons to jump from valence orbits, unlike conductors (no energy needed) or insulators (huge energy needed).
What is ‘doping’ in semiconductors?
The process of introducing impurities into an atomic lattice to modulate conductivity.
What are the two types of dopants?
n-type (electron donors) and p-type (electron acceptors (holes))
How is a diode created?
By joining p-type (anode) and n-type (cathode) semiconductor materials. Electrons and holes migrate across the junction and a depletion region is formed.
What are the two types of diode biasing?
Forward biasing - current flows more easily when anode is more positive than cathode by approximately 0.7V.
Reverse biasing - no current flows when cathode is more positive than anode.
What voltage is required for forward biasing a silicon diode?
Approximately 0.7V.
What is rectification in diodes?
The act of turning an AC voltage into a pulsed DC voltage.
How does a half-wave rectifier work?
It conducts positive half cycles and blocks negative half cycles.
How many diodes are used in a full-wave rectifier?
4 diodes.
What is the voltage drop across a forward-biased diode?
Approximately 0.7V
