Design and Tech - Electricity
Electricity: The movement of electrons, an invisible force that provides light, heat, sound, and motion
At the atomic level:
Elements: simplest form of matter
Atom: Smallest piece of an element containing all properties of an element
nucleus: center portion has protons and neutrons,
protons = positive
neutrons = neutral
movement of electrons produces electricity (on orbit negatively charged) has negative charge.
Atomic number = Number or protons
Electrons orbitals: orbits in which electrons move around nucleus of an atom
- valence electrons determines whether element is conductor or insulator
- 1st = 8, 2nd =8, 3rd = 18
- 8 tends to be magic number in orbital
- as orbits filled go further and further from nucleus
EX: 29[total electrons]-2-8-18 = 1 Valence Electron
only 1 valence electron means it wants to give it away - insulator is like a coat, conductor takes the ticket SO atoms that loose electrons (metals) are conductors. atoms that take electrons are insulators.
Sharing is caused by the conduction of heat - close enough to attract/collide
Conductors: Easily share atoms - electron flow is easy, 1-3 Valence electrons, EX: Silver, Copper, Gold, Aluminum, all metals
Insulators: Electron flow is difficult between atoms, 5-8 Valence electron, EX: Mica, Glass, Quartz, Plastic going around tools/wires,
4 Valence = semi-conductor - not good conductor or insulator but can be both
A system of conductors and components forming a complete path for current to travel:
Voltage- Volts -V:
the force (pressure) that causes current to flow- there is pressure when switch is off-pushing against pipe, tank and faucet and on-
Measuring Voltage = Multimeter
Current- Amps -A :
The flow of electrical charge measured in Amperes (A) like water: tank = battery, pipe = wiring, faucet = switch, switch closed -> stops all electrons (100s and 1000s) from leaving SO open circuit = uncomplete path = no current = no flow || closed circuit = complete path = current = flow of electrons
Conventional Current: assumes that current flows out of the positive side of the batter through the circuit and back to the negative side of the batter. INCORRECT- we will use this
Electron Flow is actually what happens. Electrons flow out of negative ide of battery through circuit tend back to the positive side of battery
both conventional current and electron flow are used. in general, science uses electron flow but engineering uses conventional current. Does not matter as long as seen in the same way consistently!!!!
Resistance- Ohms -omega:
The opposition of current flow. EX: when rock gets lodged into pipe resistance is slowing down the current/amount of water. Pressure is the same. If you were to pull a L and o straight to a batter, it would be super bright and then burst due to too much voltage - resistor necessary
resistors = components that create resistance - dims the light
makes sure there is enough current so LED or whatever it is does not pop/receive too much electricity.
V = Voltage
I = Current
R = Resistance
Voltage = Resistance x Current or V = IR
I = V/R
R = V/I
Example: Flashlight t has 6 Volt batter and has bulb with resistance of 150 ohms. How much current: I = V/R, I = 6/150, I = 0.04 Amps aka 40 mA
mili = 10 to the -3
Kilo = 10 to the 3
Components in a circuit can be connected in one of two ways:
Series Circuit: Components are connected end to end and only one single path for current to flow
Parallel Circuits: Both ends of components are connected together, multiple paths for current to flow.
OR a combination of the two
Kirchhoff's Voltage Law (KVL): Sum of all voltage drops in a series circuit equals the total applied voltage: V total = Sum of V1 + V2 + V3...
Kirchhoff's Current Law (KCL): Total current in a parallel circuit equals the sum of the individual branch currents: I total = sum of I1 + I2 + I3...
Circuit with only one path for current flow. If path is open anywhere in the circuit current stops flowing to all components.
Current flowing through every series component is equal: Total I = I1 = I2 = In -CONSTANT
Total resistance is equal to the sum of all the resistances: Total R = R1 + R2 + R3....
Sum of all voltage drops is equal to the total applied voltage - V total = V1 + V2 + V3...
-voltage drop = amount of voltage reserved for particular component (for example LED)