Electricity andElectronics

Technology Education Dept.

Bellwood-Antis Middle School

Mr. Mackereth

WHAT IS ELECTRICITY?

• ELECTRICITY is the FLOW of ELECTRONS through a current carrying CONDUCTOR or WIRE.

• ELECTRICITY CAN BE MEASURED AS…..• AMPERAGE (AMPS)- The electron’s RATE OF FLOW• VOLTAGE (VOLTS)- The PRESSURE of the electrons• POWER (WATTS)-The measure of POWER OUTPUT• RESISTANCE (OHMS)- The friction in the electric

wire while electricity is trying to pass through.

COMMOM ELECTRICAL TERMS:• POTENTIAL ENERGY- Energy in position, or

stored energy. At rest, ready to release energy• KINETIC ENERGY- Energy in motion, or

energy being consumed or used to do work.• MATTER- Object(s) that occupy space (atom)• MOLECULE- the smallest part of a compound.• ATOM- The individual elements that make up

compounds in our world. ALL MOLECULES ARE MADE FROM INDIVIDUAL ATOMS!

WHAT ARE SOME OF THE DIFFERENT WAYS OUR SOCIETY USES ELECTRICITY?

• HOUSEHOLD USES

• MANUFACTURING

• COMMUNICATION

• RECREATION

• HEALTH & MEDICAL

• PUBLIC LIGHTING

• SAFETY & SECURITY

• PROFESSIONAL USES

• TEMPERATURE CONTROLS

• RESEARCH / LABORATORY

COMMOM ELECTRICAL TERMS:• PROTONS- A positively charged particle in an atom• ELECTRONS- Negatively charged particle in an atom• DIRECT CURRENT (DC)- A continuous electrical

energy, usually from transformers and batteries• DC electric power ALWAYS flows from positive to negative• ALTERNATING CURRENT (AC)- Electricity in a wave

form that pulses from + to – 60 times a second.• Regular household/business electric power is AC• AC electricity pulses back & forth b/w positive & negative

COMMOM ELECTRICAL TERMS:

• CONDUCTOR- An object that WILL allow electric current to flow through itself. (PLASTIC, RUBBER, PVC)

• INSULATOR - An object that WILL NOT allow electric current to flow through itself. (WATER & METALS)

• ELECTRICITY QUIZ #1 IS TOMORROW!• INCLUDES EVERYTHING FROM PAGE 1 OF NOTES.

ALSO, KNOW SOCIETY’S USES OF ELECTRICITY!• BE ABLE TO DESCRIBE DIFFERENCES BETWEEN

ELECTRICAL TERMS USING COMPLETE SENTENCES.

TYPES OF CIRCUITS• OPEN CIRCUIT- An electric pathway that is not

connected, or has a break (short) in the path.

• ELECTRICITY WON’T FLOW IN AN OPEN CIRCUIT

• A light switch in the OFF position is an OPEN circuit

• CLOSED CIRCUIT- An COMPLETE electrical pathway

• ELECTRICITY WILL FLOW IN A CLOSED CIRCUIT

• A light switch in the ON position is a CLOSED circuit

TYPES OF CIRCUITS• SERIES CIRCUIT- A path with only ONE “HOT” WIRE.• Devices in a series circuit are connected one after the

other. Old Christmas lights are wired IN SERIES.• PARALLEL CIRCUIT- A path containing TWO WIRES

(one HOT & one NEUTRAL wire.) Each device is connected to BOTH WIRES. Homes are IN PARALLEL

• GROUNDED CIRCUIT- a safe circuit preventing shock• Make sure you can identify the 18 different

electrical symbols on your FLASH CARDS.

ELECTRICITY QUIZ #2• INCLUDES EVERYTHING FROM PAGES 1

& 2 OF YOUR NOTES. ALSO KNOW THE FIVE DIFFERENT CIRCUITS!• BE ABLE TO DEFINE ALL THE TERMS &

BE ABLE TO IDENTIFY ALL 18 SYMBOLS

• THE QUIZ IS TOMORROW!

CALCULATING ELECTRICAL VALUES

• Scientists discovered in the 19th century that electricity follows the laws of physics & can be calculated using mathematical equations.

• KNOW THE FORMULAS BELOW:• WATTS = VOLTS x AMPS (W = V x A)• VOLTS = AMPS x RESISTANCE (V = A x R)• If you know or are given any two of the four

values, YOU CAN CALCULATE THE OTHERS!

PRACTICE PROBLEMSPROBLEM #1

• Volts = 120 Amps = 3• FIND WATTS & OHMS• W = V x A • W =120 X 3 • W = 360

• V = A x R• 120 = 3 X R

3 3• R = 40

PROBLEM #2• Volts = 120 Watts = 60

• FIND AMPS & OHMS• W = V x A • 60 =120 X A 120 120 • A = 0.5

• V = A x R• 120 = 0.5 X R

0.5 0.5• R = 240

PRACTICE PROBLEMSPROBLEM #3

• Volts = 12 Ohms = 24• FIND AMPS & WATTS• V = A x R• 12 = 24 X R

24 24• A= 0.5

• W = V x A• w = 12 X 0.5 • W = 6

PROBLEM #4• Watts = 1200 Amps = 15• FIND VOLTS & OHMS• W = V x A• 1200 = V X 15 15 15 • V= 80

• V = A x R• 80 = 15 X R

15 15• R = 5.33333333 (5.3)

HOMEWORKPROBLEM #1

• Volts = 240 Amps = 3• FIND WATTS & OHMS• W = V x A • W =240 X 3 • W = 720

• V = A x R• 240 = 3 X R

3 3• R = 80

PROBLEM #2• Volts = 120 Watts =

180• FIND AMPS & OHMS• W = V x A • 180=120 X A 120 120 • A = 1.5

• V = A x R• 120 = 1.5 X R

1.5 1.5• R = 280

RESISTORS• RESISTORS are man-made components that are

designed to limit the flow of electricity through small circuit boards and other electronic devices.

• RESISTORS have a FOUR COLOR CODE that tells us the size (amount of resistance) in each resistor.

• COLOR BAND #1- The 1st digit in the resistor size• COLOR BAND #2- The 2nd digit in the resistor size• COLOR BAND #3- # of zeros added (multiplier)• COLOR BAND #4- The TOLERANCE level allowed

PRACTICE PROBLEM 1, a resistor withRED YELLOW BROWN SILVER 2 4 add 1 zeros 10%ANSWER: 240 Ohms with a tolerance of 10%

• HIGH TOLERANCE• # of Ohms X 100 + T%

• 240 Ohms X 110%

• Answer: 264 Ohms

• LOW TOLERANCE• # Ohms X 100 + T%

• Ohms X 110%

• Answer: 216 Ohms

PRACTICE PROBLEM 2, a resistor withBROWN RED ORANGE GOLD 1 2 add 3 zeros 5%ANSWER: 12,000 Ohms with a tolerance of 5%

• HIGH TOLERANCE• # of Ohms X (100 + T %)

• 12,000 Ohms X 105%

• ANSWER: 12,600 Ohms

• LOW TOLERANCE• # Ohms X (100 – T %)

• 12,000 Ohms X 95%

• Answer: 11,400 Ohms

HOMEWORK #1 is a resistor with …. RED RED ORANGE SILVER 2 2 add 3 zeros 10%ANSWER: 22,000 Ohms with a tolerance of 10% • HIGH TOLERANCE• # Ohms X (100 + T %)

• 22,000 Ohms X 110%

• ANS: 24,200 Ohms

• LOW TOLERANCE• # Ohms X (100 - T %)

• 22,000 Ohms X 90%

• ANS: 19,800 Ohms

HOMEWORK #2 is a resistor with …. BROWN RED BROWN SILVER 1 2 add 1 zero 10%ANSWER: 120 Ohms with a tolerance of 10% • HIGH TOLERANCE• # Ohms X (100 + T %)

• 120 Ohms X 110%

• ANS: 132 Ohms

• LOW TOLERANCE• # Ohms X (100 - T %)

• 120 Ohms X 90%

• ANS: 108 Ohms