Lecture 6 Flashcards
What is the main function of power supplies in electronic circuits?
To convert 230V AC grid voltage into DC voltage at a much lower level for electronic devices.
What are the two main types of power supplies?
Linear power supplies and switched-mode power supplies.
What are the advantages and disadvantages of linear power supplies?
They are reliable, easy to fault find and use low component count, but are heavy and bulky.
What is a transformer?
A device that transfers AC electrical energy from one voltage to another through a magnetic field.
What are the main components of a simple transformer?
Two windings (primary and secondary) wound on an iron core, electrically isolated but magnetically coupled.
What is the equation relating voltage and turns in an ideal transformer?
Vₚ / Vₛ = Nₚ / Nₛ where V is voltage and N is the number of turns for primary (Nₚ) and secondary (Nₛ) coils
What are some factors that make real transformers different from ideal transformers?
Copper losses, flux leakage, magnetisation current and eddy currents in the iron core. Typical transformers have an efficiency of around 85-95%
What is the purpose of rectifiers in power supplies?
To convert bidirectional AC voltage into unidirectional voltage.
How do semiconductors differ from conductors and insulators in terms of electron behaviour?
Semiconductors require a small amount of energy for electrons to jump from valence orbits, unlike conductors (no energy needed) or insulators (huge energy needed).
