Lesson 3 & Electrical Quantities and Ohm's Law
Amperage ( I )
1 Ampere = 1 coulomb per second Unit Symbol- a, A, amps
Formal definition of Power
1 WATT of energy is CONSUMED when 1 VOLT of electrical PRESSURE forces 1 AMP of current thru 1 OHM of RESISTANCE in 1 SECOND of time.
How fast does an electron move?
3" per hour
What is the quantity of electrons that make up 1 coulomb
6.25x10^18 or 6,250,000,000,000,000,000
How does a short circuit occur?
A short bypasses the load and permits too much current to flow.
Equation for Power
Amps x Volts = Watts
Short Circuit
An electric circuit that contains no resistance to limit the flow of current.
What causes Restrictions
Area Type Length Temperature
Force/Pressure
Comparison: Voltage in an electric circuit to pressure in a water system
For current to flow in an electric circuit, there must be a_____path.
Complete
Electrical Circuit: Closed + Open Circuits
Current flows through a closed circuit. No current can flow through an open circuit
Three possible dues to a short circuit occurring in an unprotected system
Damage equipment Melt wires Start fires
Before power or watts can exist..
Electric energy must be converted into some other form of energy. Makes no difference whether converted into heat energy or mechanical energy (horsepower)
Voltage
Electrical measurement of potential difference, electrical pressure, or electromotive force.
Electron Flow Theory
Electricity flows from the more negative part of the power source to the more positive.
Amperage
Electron Flow
In a DC circuit, how fast does electricity appear to travel
Faster than the speed of light
How much force is needed?
Foot-Pounds Requires .738 ft/lb to move 1 coulomb thru a conductor. .738 ft/lb = 1 Joule Voltage = Joule per coulomb
Voltage
Force/Pressure
What protects the power system from short circuits? (2)
Fuse Circuit breaker
Sources of electrical pressure
Generators Batteries
Grounding
Ground
3 other measures of power
Horsepower BTU (British thermal unit) Joule
Ungrounded
Hot, Feed
Symbols for Volts
Mathematic: E or V Unit: V ,v, volts
Symbols for Power
Mathematical: P or W Unit: W, w, watts
Symbols for Resistance
Mathematical: R Unit: ♎ ohms
What is a coulomb?
Measure of charge. Quantities of electrons equal to 6.25x10^18
Grounded
Neutral
The unit of measure of RESISTENCE
Ohm
Greek name for resistance
Omega
3 components needed for a basic complete circuit
Power Source Conductor Load
Resistance
Restriction
Speed of Flow
Single electron from atom to atom - moves 3" per hour The impulse of electricity travels faster than the speed of light (DC)
Coulomb
Specific quantity of electrons 1 coulomb= 6.25x10^18 electrons 6,250,000,000,000,000,000 electrons
T or F Electric energy must be changed or converted into some other form of energy such as heat energy or mechanical energy before there can be true power in watts.
TRUE
Direction of current flow
The conventional current flow theory states that surrent flows from positive to negative.🔃 The electron flow theory states that current flows from negative to positive. 🔄
Rate of Flow
The number of electrons passing through a given point in 1 seconds
What is an Ampere
Unit of measure for the rate of current flow. 1AC=1C per second
The force that pushes electrons through a circuit is called:
Voltage Electromotive force (EMF) potential difference
Terms used in Industry
Voltage Volts Potential difference Potential Electromotive Force EMFs
Power
Work Accomplished
How to create pressure
Zinc-copper cell Place two dissimilar metals in chemical soup (electrolyte) -1 electrode loses electrons (becomes positive) -the other gains electrons (becomes more negative) When an external conductive path is provided Electrons flow in a conductor from Neg. To Pos.
Unit of measure symbol to represent RESISTENCE
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