Section 3 - Electrical Elements

charge

is an electrical property of theatomic particles of which matterconsists, measured in coulombs (C)

atom

is the elementary unit of materialwhich contains the properties of thematerial

created, destroyed, transferred

charge can not be ------ nor -----, only ------.

current

defined as the time rate of flow of charge

direct current

When voltage and current in a circuit are constant (i.e., independent oftime), their values and the circuit

alternating current

When the voltage and current vary with time, usually sinusoidally, we referto their values and the circuit

electrical circuit

closed loop consisting of several conductorsconnecting electrical components

switches

Conductors may be interrupted by components called..

gravitational potential

Work done per unit mass tomove an object from a referencepoint (0 potential) to a specificpoint in a gravitational field

electric potential (Not voltage)

Work done per unit charge to move a charge from a reference point (0 potential) to a specific point in an electric field.

volatge (or potential difference)

is the energy required to move a unit chargethrough an element, measured in volts

electromotive force

voltage is sometimes referred to as...

they produce an electric current

when electrons move...

power

is the time rate of expending or absorbing energy, measured inwatts (W)

active and passive element

2 types of elements found in electric circuits are...

active element

is capable of generating energy

passive element

is not capable of generating energy

resistor, capacitor, inductors

3 examples of passive elements are...

batteries, generators

2 examples of active elements are..

independent and dependent sources

the 2 types of sources are

independent source

an active element that provides a specifiedvoltage or current that is completely independent of other circuit elements

dependent source

an active element in which the source quantity is controlled by another voltage or current

resistance

denotes its ability to resist the flow of electriccurrent

conductance

is the ability of an element to conduct electric current; it ismeasured in siemens

open circuit

any element throughwhich current cannot flow

short circuit

any element acrosswhich there is no voltage

ohms law

the voltage v across a resistor is directly proportional to the current I flowing through the resistor

capacitor

a passive element that stores energy in the form of an electric field

a pair of parallel conducting plates separated by a dielectric material

The capacitor consists of....

dielectric material

an insulator that increases the capacitance as a result ofpermanent or induced electric dipoles in the material

capacitance

the ratio of the charge on one plate of a capacitor to the voltage difference between the two plates, measured in farads (F) 1 farad= 1 coulomb/volt

inductor

passive element designed to store energy in its magnetic field

inductance

is the property whereby an inductor exhibits opposition to the change ofcurrent flowing through it, measured in henries (H)

node

A point where two or more circuit elements join

Essential node

A node where three or more circuit elements join

path

A route adjoining basic elements with no elements include more than once

branch

A path that connects two nodes

essential branch

A path that connects two essential nodes, without passing through an essential node

loop

A path whose last node is the same as the starting node

mesh

A loop that does not enclose any other loop

KVL, kirchoffs voltage law

states that the algebraic sum of all voltages arounda closed path (or loop) is zero

conservation of energy

KVL is based on

conservation of charge

KCL is based on