Physics - Circuits Flashcards
What is a series circuit?
Components that are connected one after another on the same loop of a circuit. The current is the same in all components.
What is a parallel circuit?
Components that are connected on separate loops are connected in parallel. The current is shared between each component connected in parallel.
What happens if a component breaks in a parallel and series circuit?
Series - If one component breaks the others will not work.
Parallel- If a component breaks the others will still work.
How is the voltage spread in a parallel circuit?
The voltage is the same across each branch. It is equal to the supply voltage.
What is current measured in? How is it measured?
Measured in amperes (Amps, A) using an ammeter.
What is Voltage measured in? How is it measured?
Measured in Volts (V) using a voltmeter.
What does a variable resistor do?
It can adjust the voltage or current in a circuit.
What does a graph of a resistor at a constant temperature look like?
Current is directly proportional to voltage. A diagonal line going straight through at 45 degrees.
What does the graph of a filament lamp look like?
Elongated S on an angle.
What does a graph of a diode look like?
The diode only conducts once a particular voltage has been reached. Like this: ___/
Why doesn’t a filament lamp follow Ohm’s law?
The resistance increases as the temperature increases. So the current is not directly proportional to the voltage.
How is current, voltage and resistance spread across resistors in a series circuit?
-Current in all resistors is the same. I1=I2=I3
-The total voltage across all resistors is equal to the sum of voltages across each resistor. VT = V1+V2+V3
-The total resistance across all resistors is equal to the sum of resistance across each resistor. RT = R1+R2+R3
How is current, voltage and resistance spread across resistors in a parallel circuit?
-The supply current is equal to the sum of the currents through each resistor. The currents in the branches of a parallel circuit add up to the supply current.
-When resistors are connected in parallel, they have the same voltage across them.
-The total resistance of two resistors is calculated using this equation : 1/R = 1/R1 + 1/R2
How do thermistors act at high and low temperatures?
At low temperatures, the resistance of a thermistor is high, and little current can flow through them.
At high temperatures, the resistance of a thermistor is low, and more current can flow through them.
How do LDR’s act at high and low light levels?
In the dark and at low light levels, the resistance of an LDR is high, and little current can flow through it.
In bright light, the resistance of an LDR is low, and more current can flow through it.
