PRINCIPLES OF ELECTRICITY INTRODUCTION TERMINOLOGY OHM’S LAW CIRCUITS POWER & ENERGY DIRECT CURRENT ALTERNATING CURRENT ELECTRICITY CONSTITUTES A FORM

PRINCIPLES OF ELECTRICITY

INTRODUCTION

TERMINOLOGY

OHM’S LAW

CIRCUITS

POWER & ENERGY

DIRECT CURRENT

ALTERNATING CURRENT

ELECTRICITY CONSTITUTES A FORM OF ENERGY THAT OCCURS NATURALLY ONLY IN UNCONTROLLED FORMS:

LIGHTNING

STATIC ELECTRICITY

GALVANIC REACTIONS


INTRODUCTION

TERMINOLOGYCURRENT

POTENTIAL

RESISTANCE

OHM’S LAW

CIRCUITS

POWER & ENERGY

DIRECT CURRENT

ALTERNATING CURRENT

DESCRIPTION:

ELECTRON FLOW, THE NUMBER OF ELECTRONS FLOWING PAST A GIVEN POINT.

UNITS:

AMPHERES (AMPS, A)

1 AMP = 1 COULOMB PER SECOND

1 COULOMB = 6.28 X 1018 ELECTRONS.

CURRENT


INTRODUCTION

TERMINOLOGYCURRENT

POTENTIAL

RESISTANCE

OHM’S LAW

CIRCUITS

POWER & ENERGY

DIRECT CURRENT

ALTERNATING CURRENT

DESCRIPTION:

VOLTAGE, EMF, V OR E

THE FORCE DRIVING THE CURRENT.

THIS ELECTRON MOVEMENT IS CAUSED BY CREATING A HIGHER POSITIVE ELECTRIC CHARGE AT ONE POINT ON A CONDUCTOR THAN EXISTS AT AN OTHER.

UNITS:

VOLTS

POTENTIAL


INTRODUCTION

TERMINOLOGYCURRENT

POTENTIAL

RESISTANCE

OHM’S LAW

CIRCUITS

POWER & ENERGY

DIRECT CURRENT

ALTERNATING CURRENT

DESCRIPTION:

RESISTANCE (R)

ELECTRICAL TERM FOR FRICTION.

RESISTANCE TO FLOW OF CURRENT IN AN ELECTRIC SYSTEM.

UNITS:

OHMS

RESISTANCE


INTRODUCTION

TERMINOLOGYCURRENT

POTENTIAL

RESISTANCE

OHM’S LAW

CIRCUITS

POWER & ENERGY

DIRECT CURRENT

ALTERNATING CURRENT

CONDUCTORS:

MATERIALS THAT OFFER A LOW RESISTANCE TO THE FLOW OF ELECTRIC CURRENT.

PRECIOUS METALS: SILVER, GOLD & PLATINUM.

COPPER

ALUMINUM

RESISTANCE


INTRODUCTION

TERMINOLOGYCURRENT

POTENTIAL

RESISTANCE

OHM’S LAW

CIRCUITS

POWER & ENERGY

DIRECT CURRENT

ALTERNATING CURRENT

INSULATORS:

MATERIALS THAT VIRTUALLY PREVENT THE FLOW OF ELECTRIC CURRENT.

GLASS.

RUBBER & PLASTIC: WIRE COVERING.

PORCELAIN: LAMP SOCKETS.

OIL: OIL-IMMERSED SWITCHES.

RESISTANCE


INTRODUCTION

TERMINOLOGYCURRENT

POTENTIAL

RESISTANCE

OHM’S LAW

CIRCUITS

POWER & ENERGY

DIRECT CURRENT

ALTERNATING CURRENT

PORCELAIN: LAMP SOCKETS.


INTRODUCTION

TERMINOLOGY

OHM’S LAWDESCRIPTION

SAMPLE PROBLEMS

CIRCUITS

POWER & ENERGY

DIRECT CURRENT

ALTERNATING CURRENT

CURRENT (I) = VOLTAGE (V) / RESISTANCE (R)

DESCRIPTION:

EXPRESSES THE RELATIONSHIP BETWEEN CURRENT, POTENTIAL & RESISTANCE.

THE GREATER THE VOLTAGE, THE GREATER THE CURRENT.

CONVERSELY THE GREATER THE RESISTANCE, THE SMALLER THE CURRENT.

OHM’S LAW


INTRODUCTION

TERMINOLOGY


SAMPLE PROBLEMS

CIRCUITS

POWER & ENERGY

DIRECT CURRENT

ALTERNATING CURRENT

AN INCANDESCENT LAMP HAVING A HOT-RESISTANCE OF 66 0HMS IS PUT INTO A SOCKET THAT IS CONNECTED TO 115-V SUPPLY. WHAT CURRENT FLOWS THROUGH THE LAMP?

I = V/R

I = 115/66

I = 1.74 AMPS

OHM’S LAW


INTRODUCTION

TERMINOLOGY


SAMPLE PROBLEMS

CIRCUITS

POWER & ENERGY

DIRECT CURRENT

ALTERNATING CURRENT

A TOASTER CONSTRUCTED OF A 55-OHM RESISTANCE WIRE REQUIRES 4 AMPS FOR ITS OPERATION. WHAT VOLTAGE SHOULD BE APPLIED?

V = R X I

V= 55 X 4

V = 220 VOLTS

OHM’S LAW


INTRODUCTION

TERMINOLOGY

OHM’S LAW

CIRCUITSDESCRIPTION

OPEN & CLOSED CIRCUITS

SHORT CIRCUITS

SERIES CIRCUITS

PARALLEL CIRCUITS

POWER & ENERGY

DIRECT CURRENT

ALTERNATING CURRENT

DESCRIPTION:

IN ORDER FOR ELECTRICITY TO FLOW THROUGH A CONDUCTOR UNDER A VOLTAGE DIFFERENCE, IT MUST HAVE A CONTINUOUS PATH FORMING A CLOSED LOOP OR CIRCUIT.

CIRCUITS


INTRODUCTION

TERMINOLOGY

OHM’S LAW

CIRCUITSDESCRIPTION


SHORT CIRCUITS

SERIES CIRCUITS

PARALLEL CIRCUITS

POWER & ENERGY

DIRECT CURRENT

ALTERNATING CURRENT

OPEN CIRCUITS:

INTERRUPTED

CLOSED CIRCUITS:

CONTINUITY OF PATH COMPLETE.



INTRODUCTION

TERMINOLOGY

OHM’S LAW

CIRCUITSDESCRIPTION


SHORT CIRCUITS

SERIES CIRCUITS

PARALLEL CIRCUITS

POWER & ENERGY

DIRECT CURRENT

ALTERNATING CURRENT

SHORT CIRCUITS:

WHEN A CONDUCTING MATERIAL MAKES CONTACT WITH TWO POINTS IN THE LOOP IN SUCH A WAY THAT IT FORM A SHORT CUT AROUND THE LOAD.

CURRENT IS INVERSELY PROPORTIONAL TO RESISTANCE, THUS AS RESISTANCE DROPS, CURRENT RISES.

SHORT CIRCUITS


INTRODUCTION

TERMINOLOGY

OHM’S LAW

CIRCUITSDESCRIPTION


SHORT CIRCUITS

SERIES CIRCUITS

PARALLEL CIRCUITS

POWER & ENERGY

DIRECT CURRENT

ALTERNATING CURRENT

DESCRIPTION:

CURRENT FLOWS IN AN UNDIVIDED, CONSECUTIVE & CONTINUOUS PATH FROM THE SOURCE OF ELECTROMOTIVE FORCE THROUGH THE VARIOUS LOADS & BACK TO THE SOURCE.

SERIES CIRCUITS


INTRODUCTION

TERMINOLOGY

OHM’S LAW

CIRCUITSDESCRIPTION


SHORT CIRCUITS

SERIES CIRCUITS

PARALLEL CIRCUITS

POWER & ENERGY

DIRECT CURRENT

ALTERNATING CURRENT

EVALUATION:A SINGLE INTERRUPTION CAN STOP ALL CURRENT FLOW.

CURRENT IS THE SAME EVERY WHERE IN THE CIRCUIT.

THE VOLTAGE DROP MAY BE DIFFERENT, DEPENDING ON THE VALUE OF EACH RESISTANCE, BUT THE SUM OF THE VOLTAGE DROP MUST ADD UP TO THE VOLTAGE OF THE SOURCE.

THE TOTAL RESISTANCE EQUALS THE SUM OF THE INDIVIDUAL RESISTANCES.

SERIES CIRCUITS


INTRODUCTION

TERMINOLOGY

OHM’S LAW

CIRCUITSDESCRIPTION


SHORT CIRCUITS

SERIES CIRCUITS

PARALLEL CIRCUITS

POWER & ENERGY

DIRECT CURRENT

ALTERNATING CURRENT

DESCRIPTION:

CURRENT IS DIVIDED INTO A NUMBER OF SEPARATE, INDEPENDENT BRANCHES.

EVALUATION:

IF ONE OF THE LOADS BURNS OUT OR IS DISCONNECTED, THE REMAINDER OF THE CIRCUIT CONTINUES TO FUNCTION.

PARALLEL CIRCUITS


INTRODUCTION

TERMINOLOGY

OHM’S LAW

CIRCUITSDESCRIPTION


SHORT CIRCUITS

SERIES CIRCUITS

PARALLEL CIRCUITS

POWER & ENERGY

DIRECT CURRENT

ALTERNATING CURRENT

EVALUATION:

THE TOTAL CURRENT FLOWING INTO & OUT OF THE JUNCTION POINTS OF THE BRANCHES EQUALS THE SUM OF THE BRANCH CURRENTS.

THE VOLTAGE DROP ACROSS EACH BRANCH OF A PARALLEL CIRCUIT IS EQUAL TO THE VOLTAGE OF THE SOURCE.

THE TOTAL RESISTANCE IS EQUAL TO THE RECIPROCAL OF THE SUM OF THE RECIPROCALS OF THE INDIVIDUAL BRANCHES.

PARALLEL CIRCUITS


INTRODUCTION

TERMINOLOGY

OHM’S LAW

CIRCUITSDESCRIPTION


SHORT CIRCUITS

SERIES CIRCUITS

PARALLEL CIRCUITS

POWER & ENERGY

DIRECT CURRENT

ALTERNATING CURRENT

CALCULATIONS IN PARALLEL CIRCUITS:

THE VOLTAGE IS THE SAME EVERYWHERE IN THE CIRCUIT.

THE CURRENT IN EACH BRANCH CAN BE SOLVED USING OHMS LAW: I = V/R. IF THE VOLTAGE IS 120-V AND THE RESISTANCE ON THE BRANCH IS 10-OHMS, THEN I = 120 / 10 OR 12 AMPS.

THE TOTAL RESISTANCE = ____________1______________ 1/R1 + 1/R2 + 1/R3

PARALLEL CIRCUITS


INTRODUCTION

TERMINOLOGY

OHM’S LAW

CIRCUITSDESCRIPTION


SHORT CIRCUITS

SERIES CIRCUITS

PARALLEL CIRCUITS

POWER & ENERGY

DIRECT CURRENT

ALTERNATING CURRENT

APPLICATION: STANDARD ARRANGEMENT IN ALL BUILDING WIRING.


INTRODUCTION

TERMINOLOGY

OHM’S LAW

CIRCUITS

POWER & ENERGYDEFINITIONS

RELATIONSHIP

UNITS

DIRECT CURRENT

ALTERNATING CURRENT

ENERGY:TECHNICAL TERM FOR THE MORE COMMON EXPRESSION WORK.

POWER:THE RATE AT WHICH ENERGY IS USED OR THE RATE AT WHICH WORK IS DONE.

POWER & ENERGY


INTRODUCTION

TERMINOLOGY

OHM’S LAW

CIRCUITS


RELATIONSHIP

UNITS

DIRECT CURRENT

ALTERNATING CURRENT

RELATIONSHIP BETWEEN POWER & ENERGY:

THE AMOUNT OF ENERGY USED IS DIRECTLY PROPORTIONAL TO THE POWER OF A SYSTEM AND TO THE LENGTH OF TIME IT IS IN OPERATION.

E = P X T

POWER & ENERGY


INTRODUCTION

TERMINOLOGY

OHM’S LAW

CIRCUITS


RELATIONSHIP

UNITS

DIRECT CURRENT

ALTERNATING CURRENT

POWER:

EXPRESSED IN WATTS (W) OR KILOWATTS (KW).

ENERGY:

WATT-HOURS OR KILOWATT-HOURS.

1 WATT-HOUR EQUALS 1 WATT OF POWER IN USE FOR 1 HOUR.

POWER & ENERGY


INTRODUCTION

TERMINOLOGY

OHM’S LAW

CIRCUITS

POWER & ENERGY

DIRECT CURRENTDESCRIPTION

SOURCES & GENERATION

APPLICATIONS

CALCULATIONS

ALTERNATING CURRENT

ELECTRICITY CONSTITUTES A FORM OF ENERGY THAT OCCURS NATURALLY ONLY IN UNCONTROLLED FORMS:

LIGHTNING

STATIC ELECTRICITY

GALVANIC REACTIONS

DESCRIPTION: CURRENT FLOWS ONLY IN ONE DIRECTION, AT A CONSTANT TIME RATE & VOLTAGE.


INTRODUCTION

TERMINOLOGY

OHM’S LAW

CIRCUITS

POWER & ENERGY



APPLICATIONS

CALCULATIONS

ALTERNATING CURRENT

SOURCES:BATTERY POWER.

SOME SPECIAL TYPES OF GENERATORS PRODUCE DIRECT CURRENT DIRECTLY, BUT THEIR USE IS EXTREMELY LIMITED.

RECTIFICATION OF A-C

DIRECT CURRENT


INTRODUCTION

TERMINOLOGY

OHM’S LAW

CIRCUITS

POWER & ENERGY


GENERATION

APPLICATIONS

CALCULATIONS

ALTERNATING CURRENT

DIRECT CURRENT


INTRODUCTION

TERMINOLOGY

OHM’S LAW

CIRCUITS

POWER & ENERGY



APPLICATIONS

CALCULATIONS

ALTERNATING CURRENT

APPLICATIONS:

TYPICAL FOR LOW VOLTAGE SITUATIONS.

ELEVATOR POWER: GEARLESS TRACTION MACHINES ALWAYS USE A D-C MOTOR.

SMALL AMOUNTS OF D-C ARE ALSO USED FOR CONTROLS & TELEPHONES.

DIRECT CURRENT


INTRODUCTION

TERMINOLOGY

OHM’S LAW

CIRCUITS

POWER & ENERGY



APPLICATIONS

CALCULATIONS

ALTERNATING CURRENT

FORMULA FOR CALCULATING DIRECT CURRENT POWER:

P = V X I

P = POWER IN WATTSV = VOLTAGEI = CURRENT IN AMPHERES

DIRECT CURRENT


INTRODUCTION

TERMINOLOGY

OHM’S LAW

CIRCUITS

POWER & ENERGY



APPLICATIONS

CALCULATIONS

ALTERNATING CURRENT

A 12-V BATTERY IS CONNECTED TO A 4-OHM RESISTOR. DETERMINE THE WATTAGE.

P = V X I

I= V/R = 12-V/4-OHMS = 3 AMPS

P = V X I = 12-V x 3-AMPS = 36 WATTS

DIRECT CURRENT


INTRODUCTION

TERMINOLOGY

OHM’S LAW

CIRCUITS

POWER & ENERGY

DIRECT CURRENT

ALTERNATING CURRENTDESCRIPTION

TERMINOLOGY


APPLICATIONS

CALCULATION

DESCRIPTION:

FLOW OF CURRENT IS PERIODICALLY VARYING IN TIME & IN DIRECTION.

ALTERNATING CURRENT


INTRODUCTION

TERMINOLOGY

OHM’S LAW

CIRCUITS

POWER & ENERGY

DIRECT CURRENT


TERMINOLOGY


APPLICATIONS

CALCULATION CYCLE: THE DISTANCE ALONG THE TIME AXIS SPANNED BY A POSITIVE & A NEGATIVE A-C LOOP.FREQUENCY: THE NUMBER OF CYCLES OCCURRING IN ONE SECOND (US & CANADA- 60 CYCLES/SECOND).UNITS: HERTZ (ONE CYCLE PER SECOND).

ALTERNATING CURRENT


INTRODUCTION

TERMINOLOGY

OHM’S LAW

CIRCUITS

POWER & ENERGY

DIRECT CURRENT


TERMINOLOGY


APPLICATIONS

CALCULATION

SOURCE:

A-C GENERATOR (ALTERNATOR)WHEN AN ELECTRIC CONDUCTOR IS MOVED IN A MAGNETIC FIELD, A VOLTAGE IS INDUCED IN IT.

IF THE CONDUCTOR IS FORMED INTO A COIL & ROTATED IN THE MAGNETIC FIELD, A VOLTAGE OF ALTERNATING POLARITY IS PRODUCED.

ALTERNATING CURRENT


INTRODUCTION

TERMINOLOGY

OHM’S LAW

CIRCUITS

POWER & ENERGY

DIRECT CURRENT


TERMINOLOGY


APPLICATIONS

CALCULATION

APPLICATIONS:LIGHTING.

ELECTRICAL OUTLETS.

MOST MOTORS.

ALTERNATING CURRENT


INTRODUCTION

TERMINOLOGY

OHM’S LAW

CIRCUITS

POWER & ENERGY

DIRECT CURRENT


TERMINOLOGY


APPLICATIONS

CALCULATION

DESCRIPTION:

THE CURRENT FLOW MAY LEAD OR LAG BEHIND THE VOLTAGE. THIS MEANS THAT THE AMOUNT OF POWER IS NOT AS SIMPLE TO CALCULATE AS IN A D-C CIRCUIT.

POWER FACTOR:

THE COSINE OF THE ANGLE BETWEEN THE VOLTAGE WAVE AND THE CURRENT WAVE IN A CIRCUIT. IT RANGES FROM 0.0 TO 1.0, ALTHOUGH IT IS USUALLY EXPRESSED AS A PERCENTAGE (0 TO 100%)

ALTERNATING CURRENT


INTRODUCTION

TERMINOLOGY

OHM’S LAW

CIRCUITS

POWER & ENERGY

DIRECT CURRENT


TERMINOLOGY


APPLICATIONS

CALCULATION

SINGLE PHASE POWER FORMULA:

P = V X I X PFP = POWER, IN WATTSV = POTENTIAL, IN VOLTSI = CURRENT, IN AMPSPF = POWER FACTOR, EXPRESSED AS A DECIMAL FRACTION.

ALTERNATING CURRENT


INTRODUCTION

TERMINOLOGY

OHM’S LAW

CIRCUITS

POWER & ENERGY

DIRECT CURRENT


TERMINOLOGY


APPLICATIONS

CALCULATION

IF A LAMP ON A 115-VOLT CIRCUIT DRAWS 5-AMPS AND THE POWER FACTOR IS 0.8, WHAT IS THE WATTAGE?

P = V X I X PFP = 115-VOLTS X 5-AMPS X 0.8

P = 460 WATTS

ALTERNATING CURRENT


INTRODUCTION

TERMINOLOGY

OHM’S LAW

CIRCUITS

POWER & ENERGY

DIRECT CURRENT


TERMINOLOGY


APPLICATIONS

CALCULATION

ALTERNATING CURRENT


INTRODUCTION

TERMINOLOGY

OHM’S LAW

CIRCUITS

POWER & ENERGY

DIRECT CURRENT


TERMINOLOGY


APPLICATIONS

CALCULATION

ALTERNATING CURRENT

THREE PHASE POWER FORMULA:

P = V X I X PF X 1.73P = POWER, IN WATTSV = POTENTIAL, IN VOLTSI = CURRENT, IN AMPSPF = POWER FACTOR, EXPRESSED AS A DECIMAL FRACTION.


INTRODUCTION

TERMINOLOGY

OHM’S LAW

CIRCUITS

POWER & ENERGY

DIRECT CURRENT


TERMINOLOGY


APPLICATIONS

CALCULATION

ALTERNATING CURRENT

SAMPLE PROBLEM:

A THREE-PHASE MOTOR DRAWS A CURRENT OF 7-AMPS AT 240-VOLTS. THE POWER FACTOR IS 0.8. DETERMINE THE WATTAGE.

P = V X I X PF X 1.73

P = 240-VOLTS X 7-AMPS X 0.8 X 1.73

P = 2325 WATTS

Documents

PRINCIPLES OF ELECTRICITY INTRODUCTION TERMINOLOGY OHM’S LAW CIRCUITS POWER & ENERGY DIRECT CURRENT ALTERNATING CURRENT ELECTRICITY CONSTITUTES A FORM