Quiz 10 min

Objectives Continue with Fundamentals of Electric Circuits Capacitors Inductors

Capacitors Consists of two conductive plates separated by a dielectric layer.

Dynamic System t (or ) is time

Current and voltage in the system with the capacitor

Purpose of capacitors store electrical charge or energy generate huge voltages in the circuits

Capacitors in Series and Parallel

Example Find i as a function of C , R and VB

Solving Differential Equation The transient response is the time required for the capacitor to fully charge, and is equivalent to about 5 time constants or 5T. 5T

Solution based on intuition

Magnetic Field Produced by Current An electric current in a wire produces a magnetic field around the wire that is proportional to the magnitude of the current The direction of the field follows the “right hand rule” put your thumb in the direction of the current, and your fingers wrap in the direction of the magnetic field

Electromagnet If we have a coil of wire with a current through the wire, each turn will contribute to the magnetic field and we can produce an electromagnet The magneto-motive force (mmf) is the product of the current, I, and the number of turns, N; mmf = NI

Inductors An inductor is constructed by coiling a wire around some type of form

Dynamics system v − i relationship for inductance

Inductor acts as a short circuit for DC

We need a resistor

Solving the Differential Equation time required for the inductor to get full current is equivalent to about 5 time constants or 5T.

Summary