Circuits Flashcards
What is an electrical circuit?
A closed loop that contains a power source (such as a cell), and something for the electrons to flow through (like a wire). They are generally represented with circuit diagrams.
What does the term “current” mean?
Current, denoted in the letter ”i”, is a measure of the flow of electrons around the circuit.
It is measured in amperes.
These are often called “amps” and denoted with the letter ”A”.
What does the term “potential difference” mean?
Potential difference, denoted by the letter “V”, is the force driving the flow of electrons. This is provided by the cell/battery.
Another name for potential difference is “voltage”, and is measured in volts (v).
What does the term “resistance” mean?
Resistance, denoted by the letter “R”, is everything that resists or opposes the flow of electrons.
This is measured in ohms (Ω),
What way do circuits flow?
They flow around the circuit from the positive terminal to the negative terminal.
Remember that the negative terminal is the shorter line on the cell/battery, and the positive terminal is the longer line.
To provide electric power to a circuit, what component(s) do we need?
Cell or Battery
To control the flow of electricity in a circuit, what component(s) do we need?
A switch
Switches can be closed, allowing electricity to flow, or they can be open, which turns off the circuit.
What happens to fuses if too much current flows through a circuit?
It breaks
What do diodes do in a circuit?
They only allow the current to flow in one direction.
What is an LED and what does it do?
A Light-Emitting Diode (LED) emits light when a current flows through in the forward direction.
What measures current in a circuit?
Ammeters
They are connected in series circuits.
What measures potential difference in a circuit?
Voltmeters
They are added in parallel circuits.
What are the 4 types of resistors?
Fixed Resistor, Variable Resistor, Light-Dependent Resistor and Thermistor
What do variable resistors do?
We can easily modify the amount of resistance provided in a circuit.
How does a light-dependent resistor’s resistance vary depending on the intensity of light?
In bright light environments, there is very low resistance, meaning lots of current can flow. While in darkness, the resistance is so high that hardly any current can flow.
How does a thermistor’s resistance vary depending on the temperature?
In higher temperatures, the resistance lowers allowing more current to flow through. In lower temperatures, the resistance increases.
