value from the colour coding on the resistor. 4.7.2.2 The resistance of Explain that in other 2 Draw the V–I graphs for a Required practical 15: cont. components such as lamps, types of resistor the filament lamp and a diode. use circuit diagrams to diodes, thermistors and value of R can change construct appropriate Explain the of the resulting LDRs is not constant; it as the current circuits to investigate graph in terms of resistance changes with the current changes. the I–V characteristics Teachit Science and current. through the component. of a variety of circuit resource (19977) Explain the design and Draw graphs to show how the elements including a The resistance of a filament use of circuits to ‘Electricty – resistance of an LDR will vary filament lamp, a diode interpreting graphs’ lamp increases as the explore such effects – with light intensity and of a and a resistor at temperature of the filament including lamps, thermistor with temperature. constant temperature. increases. diodes, thermistors Physics AT 6, 7 Why do the current-voltage and light-dependent The current through a diode graphs for diodes and filament resistors (LDRs). Required practical 16: flows in one direction only. lamps look different to that of use circuit diagrams to The diode has a very high an ohmic conductor? set up and check resistance in the reverse appropriate circuits to Calculate the resistance of an direction. investigate the factors LDR or a thermistor the The resistance of a affecting the resistance range of resistances for that thermistor decreases as the of electrical circuits. This component and the conditions temperature increases. should include: that it is placed in.
value from the colour coding on the resistor. 4.7.2.2 cont. 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 current through a diode flows in one direction only. The diode has a very high resistance in the reverse direction. The resistance of a thermistor decreases as the temperature increases. Explain that in other types of resistor the value of R can change as the current changes. Explain the design and use of circuits to explore such effects – including lamps, diodes, thermistors and light-dependent resistors (LDRs). 2 Draw the V–I graphs for a filament lamp and a diode. Explain the of the resulting graph in terms of resistance and current. Draw graphs to show how the resistance of an LDR will vary with light intensity and of a thermistor with temperature. Why do the current-voltage graphs for diodes and filament lamps look different to that of an ohmic conductor? Calculate the resistance of an LDR or a thermistor the range of resistances for that component and the conditions that it is placed in. Required practical 15: 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. Physics AT 6, 7 Required practical 16: use circuit diagrams to set up and check appropriate circuits to investigate the factors affecting the resistance of electrical circuits. This should include: Teachit Science resource (19977) ‘Electricty – interpreting graphs’
AQA-8465-SOW-MAI.DOCX