Electricity Flashcards
try not to fail this part of the exam.
distinguish between conductors, insulators and resistors: conductors
- materials that allow the flow of electrical currents with minimal resistance
- many free electrons(charge carriers)
- low resistance
- good thermal conductors and can transfer heat.
distinguish between conductors, insulators and resistors: insulators
materials that do not allow the flor of electrical currents easily
- very few free electrons
- high resistivity which prevents the current flow
- often used to prevent against electric shock, short circuiting
distinguish between conductors, insulators and resistors: resistors
components specifically desigened to introduce resistance into the electrical circuit.
- can be made from conductive materials but have a specific resistance value
- used to control current flor, divide voltages and protect components
- resistance quantified in ohms.
describe what is meant in terms of vlotage, current and resistance in terms of energy applied, carried and dissipated.- voltage
voltage: the measure of the amount of energy electrical potential difference between two points in a sircuit
- energy applied: can be thought of as the energy, per unit charge supploe by a power source, represents the push that drives electrical charges through a circuit.
describe what is meant in terms of vlotage, current and resistance in terms of energy applied, carried and dissipated- current
current: the flow of electric charge in a circuit
energy carried:represents tha rate at which electric charges pass through a point in the circuit, indicating how much charge is moving and carries energy through the voltage source to various components.
describe what is meant in terms of vlotage, current and resistance in terms of energy applied, carried and dissipated- resistance
resistance: opposition to the flow of electric current in a electric circuit.
energy dissipated: causes energy to be converted into heat as electric charges encounter obstacles while moving through material. the higher the resistance the more energy is dissipated in the form of heat.
Do simple calculations using Ohms law, equation V=IR.
- if voltage is doubled, current is also doubled.
- therefore current flowing is proportional to the potential difference (voltage)
V=voltage volts
I=current amps
R=resistance ohms.
Interpret circuit diagrams of series and parallel circuits. -series circuits.
- all components are connectd up one after another to form a single loop
-easiest of all circuits to connect up. - the supply voltage is split between the globes, each glove is supplied with and uses half the voltage provided by the battery
- globes cannot be controlled individually with a switch
- current stops flowing around them if a globe blows
- adding more globes reduces how brightly they glow.
Interpret circuit diagrams of series and parallel circuits- parallel circuits.
-has a number of branches, each branch has its own component.
- current leaving battery is split between the 2 globes
- each globe leaves half of the total current
- individual electrons cannot pass through both globes so it looses all its energy so only passes through one globe till the voltage requirement is met
- each globe can have its own switch
- only 1 branch is affected if the globe blows
- adding extra globes does not affect the brightness.
correctly connect the ammeter and voltmeter into series and parallel circuits in order to measure the current flowing througha nd voltage accros the resistor- ammeter.
- ammeters are always connect in series with resistors
- connect ammeter in series with the resistor to measure current flowing through
- ammeter should be part of the circuit loop.
correctly connect the ammeter and voltmeter into series and parallel circuits in order to measure the current flowing througha nd voltage accros the resistor- voltmeter
- voltmeters are always connected in parallel with resistors
- connect voltmeter win parallel across resistor to measure to voltage
- male sure the voltmeter is connected to both terminals of the resistor
Summary of Current, Voltage, and Resistance Relationships:* Current and Resistance:
- If current remains constant, an increase in resistance leads to a greater voltage drop and energy loss.
- Analogy: A rougher, steeper road uses more petrol (energy) for a car.
Summary of Current, Voltage, and Resistance Relationships: Resistance and Current Flow
- If supply voltage stays the same and resistance increases, less current flows due to difficulty for electrons to pass.
- Analogy: Roadwork or accidents reduce traffic flow, allowing fewer cars through.
Summary of Current, Voltage, and Resistance Relationships: Supply Voltage and Current
- If supply voltage increases, current flowing in the circuit increases.
- Analogy: Faster-moving cars can pass over a bridge more quickly, increasing the number of cars that cross per hour.
compare characteristics of voltage, current and resistance in series and parallel circuits.
- in series circuits, the current is the same in each part of the circuit
- in series circuits the supply voltafe equals the sum of the voltage accross the components
- in parallel circuits, the current in the branches add up to the current in the main part of the circuit
- in parallel circuits there is the same voltage across the supply and components.
