Unit 4 Electricity Lesson 6-10 Flashcards
How to identify a series circuit vs a parallel circuit
series: electrons flow through one path
parallel: -electrons flow throguh two or more paths - the current splits at a node
what do you need to have in a parallel circuit drawing
a node (threesome of wires)
what is kirchoffs’s law for a series circuit?
IT= I1 = I2= I3 (current intensity, amps)
VT=V1+V2+V3
Req= R1+R2=R3
what is kirchoffs’s law for a parallel circuit?
IT= I1+I2+I3
VT=V1=V2=V3
Req= 1/R1+ 1/R2+1/R3 (flip when solving end product)
What does R equal and what are its symbols?
R= V/I
R (resistance)= Ohms (Ω)
V(voltage)=volts (V)
I(current intensity)=amps (A)
what is power?
the amount of energy used over a period of time
how is power calculated the simpler regular way ? and its units
P=IV
P(power)=watts (W)
I(current intensity)=amps (A)
V(voltage)=volts (V)
how is power calculated the other longer ish way? and its units
P=E/T
P(power)=watts (W)
E(energy)=joules (J)
T(time)= seconds (s)
what does kWh mean and why
kilowatts per hour to calculate on appliances and hydro bill (human adulting things)
how do you get watts to kilowatts?
÷ 1000
when doing those word problems with calculating the cost of an apppliances energy you always??
multiply stuff (ex: 21 kWh x 0.08 $ = 1.75 per day)
6
list the electrical functions?
- power supply/source
- conduction
3.insulation
4.control
5.protection - transformation
6
list the power supply exemples!!
- chemical batteries
- photovoltaie cells (solar panels)
- alternators
- thermocouple
- piezoelectric
- Electrical outlets
what is a power supply?
the electrical function performed by any component that can generate or provide electric current
what is conduction?
the electrical function performed by any componenet that can transmit electric current from one part of a circuit to another
conductivity varies on what?
based on length, nature of wire, diameter and temperature of conductor
exemple of conductors
metals
wha is insulation?
the elctrical function performed by any component that prevents an electric current.
insulation is often used for what?
to cover wires to protect people from shocks and prevent short circuits
exemple of insulators
plastic, rubber, ceramic
what is control
the electrical function performed by any component that can open and close a circuit (therefore controlling the flow of electrons)
exemple of control
SWITCHES
what are the four types of switches? and picture them mentally
- flip flop (rocker) (those fat wall light switches)
- lever (the ones in the lab)
- push button (litteraly a button)
- magnetic
what is unipolar vs bipolar for switches? (picture it in your brain)
unipolar has one path for input and the bipolar has two paths for input
what is unidirectional vs bidirectional for switches? (picture it in your brain)
unidirectional is on or off for output while bidirectional is one way or another way for output
definition of a lever switch and exemple
controlled by a mechanically moving arm through a small arc ex: light switch
definition of a push button and exemple
completes an electric circuit when pressed ex: computer keyboard,doorbell
definition for flip flop switch and exemple
on/off switch that rcks (back and forth) when pressed. one side of the switch is raised while the other side is lowered ex: power bar
definiton of a magnetic switch and exemple
when the switch is near a magnetic field, two pieces of metal come in contact with each other to close the cirucit and allow the current to pass through it ex:home alarm, doors, windows, power cord on macs
what is protection
protection is the electrical function performed by any component that can automatically cut current flow in the event of a power surge
if an electrical circuit malfunctions (… or …) it could cause a .. or …
(short circuit or overload) fire or electrical shocks
what two things can be installed to prevent this from occuring?
fuses and circuit breakers
what is the function of a fuse box?
they act as a “weak link” in a circuit, designed to melt and break the cirucit if the current exceeds a safe limit so then a fuse must be replace if it is blown
desribe the mechanism of a fuse box and exemple of metal
They contain a thin wire or strip of metal that has a low melting point. When excessive current flows, the metal (lead) heats up rapidly and melts, creating a break in the circuit and stopping the flow of electricity.
unlike a fuse a breaker can be …
RESET
how do circuit breakers work?
when the current get too strong, a bimetallic strip becomes hot and bends to disconnect the circuit
what is transformation of energy
the electrical function performed by any component that can convert electrical energy into another form of energy
give an exemple of transformation of energy
electrical energy to radiation/thermal energy (toaster)
function of a diode
- inserted into electrical circuits causing current to flow in one direction
what are diodes like
a turnstile (in the metro): a person can exit or enter but not do both
what are diodes usually made of
semiconductor material like silicon
give two exemples of a diode
- batter operated devices
- light emitting diodes (LEDs)
what is the drawing for diodes
->I-
what is the function of capacitors (condensers)
stores electric charge
what is a capacitance
the amount of charge that can be stored
what are capacitors compsoed of
two electrical surfaces seperated by an insulating material
the charge stored ona capacitor’s plate can be…
discharged or charging
the current flows from
negative to positive to make the lightbulb shine
what is the drawing fro a capacitor
-II-
2 exemples of capacitors
- camera flashes
- defibrillators
what are the 2 fuctions of a transistor
- Amplifier: they take a small electric current and produce a much bigger current (hearing aids use this function to amply sound)
- Switch: a small electric current flowing through one part of a transistor can make a much bigger current flow through another part of it. the small current switchs on the larger one (computer chips contain these)
what is AC stand for
alternating current
what does DC stand for
direct current
AC vs DC explain
- in DC, the electrons flow in one direction around a circuit (the voltage remains the same)
- while in AC, the direction of electron flow around a circuit is continuously switching
what usually generate AC
POWERPLANTS
what type of component would be used to convret AC to DC
DIODES
batteries produce …
wall sockets produce…
batteries produce DC
wall sockets produce AC
its easier to transport electricity in
AC across long distances (the voltage is kept high so the current is lower and as a result less energy is lost) transformers convert high to low voltages
