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P4-Electrical circuits - Coggle Diagram
P4-Electrical circuits
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Current, resistance and potential difference
Required practical activity 15: use circuit diagrams to set up and check appropriate circuits to investigate the factors affecting the resistance of electrical circuits. This should include: • the length of a wire at constant temperature • combinations of resistors in series and parallel 
The current (I) through a component depends on both the resistance (R) of the component and the potential difference (V) across the component
how does the resistance of the component affect current for a
given potential difference (pd) across the component?
what equation links current, potential difference or resistance and name the units?
Resistors
Required practical activity 16: use circuit diagrams to construct appropriate circuits to investigate the I–V characteristics of a variety of circuit elements, including a filament lamp, a diode and a resistor at constant temperature
explain that, for some resistors, the value of R remains constant but that in others it can change as the current changes
ohmic conductors
The current through an ohmic conductor (at a constant temperature) is directly proportional to the potential difference across the resistor. This means that the resistance remains constant as the current changes.
draw the graph
filament lamp
draw the graph
The resistance of components such as lamps, diodes, thermistors and LDRs is not constant; it changes with the current through the component. The resistance of a filament lamp increases as the temperature of the filament increases.
The resistance of a thermistor decreases as the temperature increases (TURD). What is a use for a thermistor?
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diode
draw the graph
The current through a diode flows in one direction only. The diode has a very high resistance in the reverse direction.
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