2. Electricity (current and circuit symbols, IV characteristics) Flashcards
What is current?
It is the flow of electrical charge (electrons)
What is voltage?
The driving force that pushes the electrons
What is resistance?
It slows down the flow of current
What is the equation for finding charge flow?
Q = IT
Charge (C) = current (A) x time (s)
What is charge flow measured in?
Coulombs (C)
What is current measured in?
Amps (A)
What is time measured in?
Seconds (S)
What circuit symbol is this and what does it do?
A cell - which pushes electrons from the negative to positive terminal
What circuit symbol is this and what does it do?
A switch - when closed it allows current to flow through
What circuit symbol is this and what does it do?
A filament bulb - it emits light when current passes through it
What circuit symbol is this and what does it do?
A diode - it only allows current to flow in one direction
What circuit symbol is this and what does it do?
A light emmiting diode (LED) - it emits light
What circuit symbol is this and what does it do?
An ammeter - it measures the current
What circuit symbol is this and what does it do?
A fixed resistor - it limits the current which flows through the circuit
What circuit symbol is this and what does it do?
A variable resistor - you change the resistance so varies the current flowing through it
What circuit symbol is this and what does it do?
A fuse - it is a circuit break, as if the current is too high, the wire (inside the box) will melt
What circuit symbol is this and what does it do?
A thermistor - it transfers electrical energy to heat
What circuit symbol is this and what does it do?
A voltmeter - it measures the voltage flowing through a circuit
What circuit symbol is this and what does it do?
A light dependent resistor (LDR) - it measures the light intensity
What is the equation for potential difference?
V = IR
potential difference (V) = current (A) x Resistance (ohms)
What is a super conductor?
A material that conducts electricty with very little resistance at a very low temperature
What are the factors affecting resistance?
- temperature
- length of wire
- diameter of wire
How does temperature affect resistance?
As temperature increases, resistance increases
What are IV characteristics?
Characteristics of voltage and current
What are the IV characteristics for an Ohmic conductor?
Current and voltage are directly proportional to one another
What are the IV characteristics for a Filament bulb?
As current increases, temperature increases, this increases the resistance, so less current is able to flow through
What are the IV characteristics for a Diode?
It only allows current to flow in one direction and in the other direction there is a very high resistance
Which component is the IV characteristics graph showing for?
An ohmic conductor
Which component is the IV characteristics graph showing for?
A filament bulb
Which component is the IV characteristics graph showing for?
A diode
