CIRCUITS

Resistance

is the property of a material that impedes the flow of current

Material, Length, Cross-sectional area, temperature of the material

these are the factors that affect resistance of any material

Electric circuit

is an interconnection of electrical elements

Should have: voltage/current source, load, connection from load to source, closed, means to control the flow of current

characteristics of electric circuit

deka 

10^(1)

hecto 

10^(2)

Kilo

10^(3)

mega

10^(6)

giga

10^(9)

tera

10^(12)

peta

10^(15)

exa

10^(18)

zetta

10^(21)

yotta

10^(24)

deci

10^(-1)

centi

10^(-2)

mili

10^(-3)

micro

10^(-6)

nano

10^(-9)

pico

10^(-12)

femto

10^(-15)

atto

10^(-18)

zepto

10^(-21)

yocto

10^(-24)

fixed-point

format requires that the decimal point appear in the same place each time

floating-point

format, the decimal point appears in a location defined by the number to be displayed

Scientific

(also called standard) notation and engineering notation make use of powers of ten, with restrictions on the mantissa (multiplier) or scale factor (power of ten)

Charge

¡is an electrical property of the atomic particles of which matter consists,

Charge

measured in coulombs (C)

time varying

charge symbol q is for

constant charge

charge symbol Q is for

proton

positive subatomic particle

electron

negative subatomic particle

neutron

neutral subatomic particle

6.24 × 10^(18)

1 Coulomb is equal to ____ electrons or protons

2n²

the number of electrons in each succeeding shell is determined by

copper

the most commonly used metal in the electrical/electronics industry

positive ion

This positive region created by separating the free electron from the basic atomic structure is called a

voltage

is established by simply creating a separation of positive and negative charges

Current

defined as the movement of electric charge

Direct current and Alternating current

two most common currents

Direct current

current that remain constant with time

Alternating current

current that varies sinusoidally with time

Conventional flow and electron flow

directions of current

conventional flow

positve charge movement

electron flow

negative charge movement

Batteries, generators, power supplies

3 basic types of DC voltage sources

battery

consists of a combination of two or more similar cells, a cell being the fundamental source of electrical energy developed through the conversion of chemical or solar energy

DC generators

When the shaft of the generator is rotating at the nameplate speed due to the applied torque of some external source of mechanical power, a voltage of rated value appears across the external terminals

Power supplies

the dc supply encountered most frequently in the laboratory uses the rectification and filtering processes as its means toward obtaining a steady dc voltage

ampere-hour (Ah)

rating provides an indication of how long a battery of fixed voltage will be able to supply a particular current

ampere-hour (Ah)

is basically a unit of charge of a battery

current demand and temperature

battery life factors

active element and passive element

electric elements can be classified as

active element

capable of generating energy. Example of which are the voltage source, current source, generators, batteries and amplifiers.

passive element

is not capable of generating energy. Examples are resistors, capacitors and inductors.

ideal independent and ideal dependent (controlled source)

two kind of sources

ideal independent source

is an active element that provides a specified voltage or current that is completely independent of other circuit elements.

ideal dependent (or controlled)

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

Voltage-controlled voltage source

current-controlled voltage source

voltage-controlled current source

current-controlled voltage source

four dependent sources

+

symbol for dependent voltage source

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symbol dependent current source

power

rate at which work is done

positive convention for power

power is being absorbed by the element

negative convention for power

power is being supplied by the element

conductor

are those materials that permit a generous flow of electrons with very little applied voltage.

Insulators

are materials that have few free electrons and require large applied voltage to establish a measurable current level.

Semiconductors

are those materials that exhibit characteristics between those of conductors and those of insulators.

ammeter

is an instrument for measuring current levels. is inserted to the path where the current is to be measured.

Voltmeter

is used for measuring voltages. It is connected in parallel to the element where the voltage is to be measured.