28 terms

# Circuits

Learning Objective(s): • Draw and interpret circuit diagrams containing sources, switches, resistors (fixed and variable), lamps, ammeters, voltmeters and fuses. • Explain why the current at every point in a series circuit is the same. • Explain why the current from the source is larger than the current in each branch in a parallel circuit. • Compare the advantages of connecting lamps in series or parallel in a lighting circuit. • Describe the sum of the p.d.s across the components in a series…
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• a complete and closed path around
which a circulating electric current can flow
(• a system of electrical conductors and components)
Define "circuit"
An electric current will only flow if there is a COMPLETE, UNBROKEN electric circuit, that contains a POWER SUPPLY
An electric current will only flow if there is a ... electric circuit, that contains a ...
A circuit diagram uses a standard set of SYMBOLS to show how ELECTRICAL COMPONENTS ARE CONNECTED TOGETHER
A circuit diagram uses a standard set of ... to show how ...
• from + to -
Which direction is the current flow drawn on a circuit diagram?
• components are connected in a series (nothing going parallel)
Define "series circuit"
• the same electric current passes through each component
Explain the current flow through a series circuit
• each component shares the voltage of the power supply
Explain the voltage flow through a series circuit
is one with several different paths for the electricity to travel
Define "parallel circuits"
• the same voltage passes through each component
Explain the voltage flow through a parallel circuit
• current is shared by each parallel circuit
(• the total current through the whole circuit is the sum of the currents through the separate components)
Explain the current flow through a parallel circuit
• the lamps (components) are brighter in parallel than when connected in series
• the lamps (components) can be controlled individually with switches
• one lamp (components) will continue working even if the other does not
∙If one of the parallel paths is broken, current will continue to flow in all the other paths
What are the advantages of parallel circuits?
The current
What do you call the electricity going round the circuit
The battery
What pushes the electrical current round the circuit
Voltage
What is the strength of push called provided by the battery
Rheostat
What is another name for a variable resistor?
Amps
What is the unit for current?
A
What is the symbol for amp?
Ammeter
What instrument is used to measure amps?
The ammeter is always connected in series
How do you measure the current through a component using an ammeter?
Voltmeter
What do you measure voltage with?
Voltmeter is always connected in parallel
How do you measure the voltage across a component using a voltmeter
Increases the current that flows in the circuit
What happens when you increase the number of cells in a circuit?
Voltage
What does the current depend on?
Yes
Is the current the same in all parts in a series circuit?
the current depends on the voltage
the current/voltage depends on the current/voltage ?
The current splits evenly
If the bulbs are identical in a parallel circuit what happens to the current?
The current will not split evenly
If the bulbs are not identical, in a parallel circuit what happens to the current?
The current that leaves the cell is the same as the current that returns to the cell
What is true of a parallel circuit in terms of the strength of the current?