Topic 1-3 Review Flashcards
What are the main types of circuit components?
Source, Conductor, Load, Control
Source: power supply, Conductor: wire, Load: converts electrical energy into other forms of energy, Control: switch or device that can turn loads on or off.
What is the symbol for current?
I
Current is measured in amps (A) or milliamps (mA).
What tool is used to measure regular current?
Ammeter
A galvanometer measures very weak current.
What is the definition of electrical current?
The amount of charge that passes a point in a conducting wire every second
Measured in amps.
What is the symbol for voltage?
V
Voltage is measured in volts (V).
What tool is used to measure regular voltage?
Voltmeter
A millivoltmeter measures smaller voltages.
Define potential difference.
The difference in energy per unit of charge between one point and another in the circuit
Also referred to as voltage.
In the river metaphor, what does current represent?
The flow rate of the river (volume/time)
Current does not change in a series circuit but is split among pathways in a parallel circuit.
How does current behave in a series circuit?
Current doesn’t change
All components share the same current.
How does current behave in a parallel circuit?
Current is split among the pathways
Total current is the sum of the currents through each pathway.
What is static electricity?
Build up of charges on a material
It differs from current electricity, which is the flow of electrons.
What is current electricity?
Flow of electrons through a material
It is different from static electricity.
What are conductors?
Materials that allow electrons to flow freely
Examples include copper, gold, aluminum.
What are insulators?
Materials that do not allow electrons to flow well
Examples include cotton, glass, rubber.
What are the two types of circuits?
Series and Parallel
Series circuits provide a single path, while parallel circuits provide multiple paths for electrons to travel.
In a parallel circuit, how does the current change with load?
Current (amps) decrease with load/pathway
This is due to the division of current among multiple paths.
What does voltage represent in the river metaphor?
Like the dam in a river
The height of the dam represents the energy potential.
Fill in the blank: Current electricity is the flow of electrons through a _______.
Conductor
This is in contrast to static electricity.
What are the four main materials and devices used to control electrical current?
Insulators, conductors, resistors, switches
What are conductors?
Materials that allow the flow of electrons
Name four examples of excellent conductors.
- Copper
- Aluminum
- Silver
- Mercury
What are superconductors?
Materials that have no resistance to electron flow when cooled to near Absolute Zero
At what temperature is Absolute Zero defined?
-273°C
What are insulators?
Non-conductive materials that prevent the flow of electrons
Name some good insulating materials.
- Wood
- Glass
- Rubber
- Certain plastics
What is the function of resistors?
They limit the flow of electrons by allowing only some to pass through
What happens to electrons in a resistor?
They are slowed down and restricted in movement
Give two examples of devices that use resistors to produce light and heat.
- Light bulb
- Stove element
What is a rheostat?
A variable resistor that controls the amount of current passing through a circuit
Provide two examples of a rheostat.
- Light dimmer switch
- Radio volume control
What is the function of a switch in an electrical circuit?
To turn on or off electrical devices by breaking or opening the circuit
What does Ohm’s Law state?
Current flowing through a wire varies directly to the voltage applied
What is the formula for Ohm’s Law?
V = I × R
What happens to current if resistance increases, according to Ohm’s Law?
The current decreases
What is the voltage of a power source with a 1.5 A current flowing through a 30 Ω lamp resistance?
45 V
What is the amount of current passing through a hair dryer with a resistance of 12 Ω plugged into a 110 V outlet?
9.17 A
What is the resistance in a radio circuit that uses a current of 0.2 A and is operated by a 9 V battery?
45 Ω
