Electricity Flashcards
Define cell
Power generating component which converts stored chemical energy into electrical energy
Define battery
2+ electrical cells joined to generate power and convert chemical energy into electrical energy
Define resistor
Component that has electrical resistance and that is used in a electric circuit for protection, operation or current control
Define switch
Electrical component that can disconnect or connect the conducting path in an electrical circuit, interrupting the electric current or diverting it from one conductor to another.
Define lamp
Component that converts electrical energy into light and heat energy
Define buzzer
An audio-signaling component
Define motor
An electro-mechanical component which converts electrical energy into mechanical energy
Define generator
A device that converts mechanical energy into electrical energy for use in an external circuit
Define solar cell
Also known as a photovoltaic cell, it is a component that converts light energy directly into electricity
Define transistor
Component used to control the flow of current and has the ability to amplify a current
Define LED
Light Emitting Diode, a component which emits light when current passes through it. Also only allows current to flow in one direction
Define LDR
Light-Dependent Resistor, controls the flow of current and has the ability to act as a switch. It’s functionality is dependent on the amount of light that hits the surface.
Define thermistor
Type of resistor whose resistance changes with temperature
Define capacitor
Component that stores energy for a short period of time and then releases it
Define parallel circuit
More than one pathway to flow.
Define series circuit
Only one pathway to flow. One component after another.
Give advantages and disadvantages of a series circuit.
ADVANTAGES:
Easier to switch on/off - all appliances connected together
Safer - less current flows through circuit
Used when 100s/1000s of bulbs are to be used together, so that the same current passes through all, and can be switched on/off together
DISADVANTAGES:
Electrical appliance stop working = all stop working
All electrical appliances have only 1 switch = cannot be turned on/off separately
All appliances do not get the same voltage - voltage divided in series combination
Equivalent resistance increases too much = amount of current flowing becomes very small
Give advantages and disadvantages of a parallel circuit.
ADVANTAGES:
Even if one appliance stops working, all others work fine
Individual appliances can be turned on/off separately
Each electrical appliance gets the same voltage as the power supply line.
Resistance of circuit decreases = appliances can draw more current to operate
DISADVANTAGES:
Method becomes cumbersome to use if thousands of bulbs/appliances are to be switched on/off
Less safe - more current can pass through circuit
Describe the difference for cells when they are in series or in parallel.
IN SERIES:
Connected when the + terminal is connected to the - terminal of another cell
IN PARALLEL:
Connected when the + terminal of one cell is connected to the + terminal of another cell. And the - terminals are also connected
Describe the difference for the potential difference when they are in series or in parallel.
IN SERIES:
Voltage added together = amount of energy will be greater throughout the circuit
IN PARALLEL:
Voltage remains the same = Amount of energy will be equally distributed throughout the circuit
Describe the difference for bulbs when they are in series or in parallel.
IN SERIES:
Connected when the one terminal of a bulb holder is connected to the terminal of another bulb holder in a straight line.
IN PARALLEL:
Connected when the terminals of the bulb holders are placed across one another.
Define logic gates
Electronic switch that is an assembly of switches connected in a specific way
Define AND logic gate
Consists of 2 electronic switches connected in series
Both switches have to be closed for the circuit to be active
Switch A AND B has to be in the same state
Define OR logic gate
Consists of 2 electronic switches connected in parallel
Either one of the switches must be closed for the circuit to be active
Switch A OR B has to be closed
Define potential difference
Also known as voltage
Measured with a Voltmeter, connected in parallel
Measured in Volts (V)
Symbol: V
Define current
Rate of flow of an electric charge past a (one) point in a circuit
Measured with an Ammeter, connected in series
Measured in Amperes (A)
Symbol: I
Current flows from + to negative = conventional flow
Define resistance
Slows down the flow of charge in a circuit
Measured with an Ohmmeter
Measured in Ohms
Symbol: R
Define Ohm’s law
As voltage increases, current increases, only if resistance is constant
OR
The current in a circuit is directly proportional to the voltage, and inversely proportional to the resistance, provided that the temperature is kept constant
What is the formula for current?
I(current) = V(voltage) / R(resistance)
What is the formula for voltage?
V(voltage) = I(current) x R(resistance)
What is the formula for resistance?
R(resistance) = V(voltage) / I(current)
