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Science Dynamic Electricity - Coggle Diagram
Science Dynamic Electricity
All the phenomena related to electrical charges in motion- when charges are placed in a circuit, they flow in a loop
Electric current is the orderly flow of negative charges carried by electrons
Due to the force of repulsion between charges, the electrons in a circuit are constantly pushed from one atom to the next
As soon as current is generated at one point in a circuit, all electrons in the loops are set in motion
Electron flow notation is based on our present understanding that the moving particles are negative (aka electrons);
therefore the ACTUAL direction of current is from the negative terminal of the power supply to its positive terminal
Conventional current direction is the direction a POSITIVE particle would flow, opposite to electron flow notation
From the positive terminal of a power supply to its negative terminal
Current intensity
Refers to the number of charges that flow past a given point in an electrical circuit per second
An ammeter is an instrument used for measuring current intensity.
It counts the number of charges that flow past a given point in a circuit in one second.
It must be installed in series
Analogy
The current intensity is described by the number of delivery trucks passing a given point along a delivery route per second (
Trucks=charges
)
Potential difference is the difference in the number of boxes a delivery truck is carrying before and after a delivery. (
boxes=energy
)
A higher resistant circuit element means the bigger the delivery because there are more boxes of energy being unloaded per delivery truck. There is a slower flow of delivery trucks (
High resistance=big delivery bc of high potential difference=a large number of boxes unloaded per delivery truck and slow flow of delivery truck=lower current intensity
)
The equivalent resistance is described as the hindrance to flow of delivery trucks associated with one big store that could replace the collection of smaller stores along the delivery route
Unit of measurement
Current intensity is in
Ampere (A)
One Ampere is EQUAL to a charge of one COULOMB flowing through the circuit every SECOND
A=C/s
Determining current intensity with a formula:
I = q/t
Potential difference is in
Volts
One volt is EQUAL to the energy of one JOULE per COULOMB
V=J/C
Determining the potential difference with a formula:
V= E/q
Resistance according to Ohms Law in
Ohm
One ohm us EQUAL to a potential difference of one VOLT per AMPERE
Ohm=V/A
Determining resistance with formula:
V=RI
electrical power in
Watts
One watt is EQUAL TO one JOULE per SECOND
W=J/S
Determining electrical power with formulaS:
Pe=W/t
Pe=VI
Electrical Energy in
Joules or Kilowatt hours
One joule is EQUAL to one Watt times one second
Determining the electrical power with the formula:
E=PeT
One kilowatt hour is EQUAL to one KW times one HOUR
In a series circuit
The current Intensity is the same at any point in the circuit and can be determined with formula:
It=I1=I2+I3...
The potential difference is the sum of individual potential differences in the circuit:
Vt=V1+V2+V3...
The equivalent resistance is the sum of the individual resistances in the circuit:
Req= R1+R2=R3
Potential difference
Is the difference in the amount of energy per charge from one point in an electrical circuit to another
As charges flow through a circuit they give eneregy to elements such as light bulbs, heaters, even the wire itself
A volt meter is an instrument used for measuring potential difference
It measures the amount of energy each charge transfers to a circuit element
It must be installed in parallel, from one side of the circuit element to the next
resistance
A measure of how a circuit element or material reduces the electric current flowing through it. Factors affect the electrical resistance and conductance of a circuit
Nature of substance: poor conductor increases resistance to current flow vs good conductor increases conductance
Length: a longer wire will increase resistance vs a shorter wire will increase conductance
Diameter: a smaller wire will increase the resistance vs a larger wire will increase conductance
Temperature: Warmer temperatures will increase resistance vs colder temperatures will increase conductance
A higher resistance circuit element means more energy per charge being transferred to that element and a lower current intensity (
aka increase resistance=increase potential difference=decrease current intensity
)
Circuit components called resistors TRANSFORM energy into another form such as thermal, light or mechanical which results in a DROP in the amount of energy carried by charge
The greater the number of resistors, the lower the energy distributed aka decrease in potential difference
Electrical power
Rate at which electrical energy is consumed by a device
Circuits
Contain
3 components
A power supply to create a potential difference (measured in volts)
One or more elements that use electrical energy such as light bulb (their resistance is measured in ohms)
Wires that carry the charges from power supply to elements and them from elements back to power supply (current intensity measures in amperes)
Diagrams and symbols are used to represent electrical circuits, and current direction usually corresponds to
conventional current direction
Series
A circuit in which the elements are connected end to end.
The current can follow ONLY ONE PATH
Characteristics:
If even one circuit element is defective, the ENTIRE circuit STOPS working bc the charges CAN NO LONGER FLOW
The energy used by the resistors ADD UP so that with each new resistor the amount of ENERGY IS REDUCED
Parallel
A circuit that contains at least one branch
The current may follow MORE THAN ONE PATH
The points at which a circuit separates and merges are called NODES
Characteristcs
If an element of the circuit is defective, the elements in the other branches CONTINUE FUNCTIONING because the current still flows through them