Electricity - Circuits Flashcards
Describe the function of a cell.
Pushes current around a circuit.
What is a variable resistor?
A resistor that can be adjusted in a circuit.
Describe the symbol of a cell.
- |I-
What does the symbol for a battery look like?
- |I-|I-
What component is this symbol?
^
\_\_\_\_/\_\_\_
- |\_\_\_/\_\_\_| -
/Variable Resistor
What is the function of the variable resistor?
A resistor that can be adjusted
If a switch in a series circuit is closed, is the bulb turned on or off?
On, as electrons (current) can pass through.
What does LDR stand for? What does it do?
Light Dependent Resistor
Changes the resistance in a circuit depending on the intensity of the light around it.
Describe the symbol of an LDR.
- Resistor symbol in a circle, with two, diagonal arrows on the left side.
What is the function of a fuse in a circuit?
Describe the symbol.
- Safety precaution (a fuse will break if there is too much current flowing through it, protecting the user from electric shock)
- The symbol for a resistor, but the line continues through the rectangle
What does an Ammeter measure? Which type of circuit can you place an ammeter in?
- Measures the current (amps)
- In a series circuit
Describe the symbol for a thermistor.
- “Hockey Stick”
- Resistor, with this shape through it _/
Describe the function of a thermistor.
Changes the resistance in a circuit based on the temperature it is exposed to.
What does a resistor do?
Makes it more/less difficult for current to pass through
What is the function of a diode?
Ensures current only flows one way
Describe the symbol of a Diode
-O-
Inside the “O” is >|
The “>” is a full triangle
Describe the symbol of an LED. State its function.
- Diode symbol, with two arrows ( // ) on the right side
- Light Emitting Diode - Convert electrical energy directly into light
What does a voltmeter measure? Where do you place it within a circuit?
Measures the voltage (volts)
Is placed in parallel to a pre-existing circuit.
What happens to voltage in a series circuit?
Voltage is shared by components
E.g. if there were two bulbs in a series circuit, an initial voltage of 7V could be shared 3V and 4V, as not all bulbs are the same.
What happens to the voltage in a parallel circuit?
Each branch gets the maximum voltage.
E.g. if the battery had a voltage of 7V, every branch would get 7V.
What would the current do in a series circuit?
Current is the same everywhere in the circuit.
What does the current do in a parallel circuit?
The current splits and recombines at junctions in the circuit.
Describe the resistance in a series circuit.
The total resistance is the resistance in every resistor added together.
Describe the resistance in a parallel circuit.
The total resistance is less than the smallest resistor
Define an ohmic resistor.
Resistors that follow a DIRECTLY PROPORTIONAL relationship between voltage and current. ↗️
Define a non-ohmic resistor.
Any resistors that DO NOT follow the directly proportional relationship between voltage and current.
True or False - A resistor has a directly proportional relationship between voltage and current.
TRUE
Describe the graph of the relationship between voltage and current in a filament lamp.
(3 marks)
…………………………..➡️➡️ ………………………↗️ ………………….↗️ ……………….⚫️ …………….↗️ ………..↗️ ➡️➡️
~The voltage increases, which causes the bulb gets hotter so the resistance increases.
Describe the graph of the relationship between the voltage and the current in a diode. (3 marks)
…………………↗️
…………….↗️
➡️➡️⚫️
1- Negative Current
2- Directly proportional from the origin.
~As the diode only allows current one way, the resistance the one way is high, but is 0 the other way.
Describe the relationship between resistance and light in an LDR.
Light ⬆️
Resistance ⬇️
Why does a filament lamp IV graph curve?
Because the filament lamps temperature increases when the voltage in the circuit does, so the resistance then changes too.
