Electrical Quantities and Ohm's Law Flashcards
Ampere
unit of measure for rate of current flow
1 A = 1 C/s
British Thermal Unit (BTU)
amount of heat required to raise 1 pound of water 1 degree F
Complete Path
path that exists in a circuit when it can be traced from one terminal of a power source to another
Conventional Current Flow Theory
theory that considers current to flow from positive to negative
Coulomb
quantity of electrons equal to 6.25 x 10E18
Electromotive Force (EMF)
electrical pressure
the fore that pushes electrons through a wire
EMF aka
voltage
Electron Flow Theory
electricity flows from negative to positive
Grounding conductor
conductor that is used to force a piece of equipment to exist at ground potential; usually green in colour
Horsepower
measure of power for electrical and mechanical devices
1 hp equals how many watts
746 W
1 hp equals how many ft-lbs/s
550 ft-lbs/s
Impedance
the total opposition to current flow in an electric circuit
Joule
basic unit of electrical energy
amount of work done when 1 A flows through 1 Volt for 1 second
Neutral conductor
grounded conductor of a power system
connected to ground potential and is considered to be a current-carrying conductor
Ohm
unit of measure for electrical resistance
Ohm’s law
set of electrical laws that permits electrical quantities to be calculated mathematically
Potential difference
difference between positive and negative charges developed by a power source
Power is measured in what unit
watts
Power
describes amount of electrical energy converted to some other form
Resistance
opposition to current flow in an electrical circuit
Volt
measure of EMF
potential necessary to cause 1 C to produce 1 J of energy
Watt
measure of true power
Coulomb’s law
force of electrostatic attraction or repulsion is directly proportional to the product of the2 charges and inversely proportional to the distance between them
What is the SI unit of electrical charge
the coulomb
1 Coulomb is defined as
the amount of electric charge that is transferred by a current of 1 ampere in 1 second
1 Amp equals
1 C/s
Conventional current flow theory
current flows from the positive terminal to the negative one
Electron flow theory
current flows from the negative terminal to the positive
In a circuit, what condition must be met for current to flow
there needs to be a complete path, aka a closed circuit
Components of a basic circuit
load
switch
conductor
power source
Short circuit
when there is little to no resistance in a circuit which leads to excessive current flow
Voltage aka
potential difference
EMF
The force that pushes the electrons through a wire is
the voltage
What letter represents voltage in mathematical equations
E
What happens when there is little to no resistance in a circuit
excessive amount of current flows causing a short circuit
How are resistance and current related
they are inversely proportional
if R increases, current decreases and vice versa
What is produced as current flows
heat
Power formula
P = E x I
(power = volts times amps, or volts times current)
calorie
amount of heat required to raise the temperature of 1 g of water by 1 degree C
Ohm’s law: volts and amps
1 volt is required to push 1 Amp through 1 ohm
Ohm’s law formula
E = IR
(volts = amps times resistance)
A _________ ________ must exist before electricity can flow through a circuit
complete path
A circuit with a complete path for electrical flow is called a ________ _______
closed circuit
If a circuit path is incomplete or broken it is an ______ _____
open circuit
Can electrons flow through an open circuit
no they cannot
Volt/Voltage is also known as
electrical pressusre
What does Ohm’s law state
the current flowing through a circuit is directly proportional to the voltage and indirectly proportional to the resistance
Kilo
1,000
Hecto
100
Deca
10
Deci
0.1 or 1/10
Centi
0.01 or 1/100
Milli
0.01 or 1/1000
Micro
10E-6
Mega
Million or 10E6
