Electric Circuits Questions Cambridge IGCSE O level Physics 0625 0972 5054 Lesson 64 part a

4.3 Electric circuits
4.3.1 Circuit diagrams
Core
•• Draw and interpret circuit diagrams containing
sources, switches, resistors (fixed and variable),
heaters, thermistors, light-dependent resistors,
lamps, ammeters, voltmeters, galvanometers,
magnetising coils, transformers, bells, fuses and
relays
Supplement
•• Draw and interpret circuit diagrams containing
diodes
4.3.2 Series and parallel circuits
Core
•• Understand that the current at every point in a
series circuit is the same
•• Give the combined resistance of two or more
resistors in series
•• State that, for a parallel circuit, the current from
the source is larger than the current in each
branch
•• State that the combined resistance of two
resistors in parallel is less than that of either
resistor by itself
•• State the advantages of connecting lamps in
parallel in a lighting circuit
Supplement
•• Calculate the combined e.m.f. of several sources
in series
•• Recall and use the fact that the sum of the p.d.s
across the components in a series circuit is equal
to the total p.d. across the supply
•• Recall and use the fact that the current from the
source is the sum of the currents in the separate
branches of a parallel circuit
•• Calculate the effective resistance of two resistors
in parallel
4.3.3 Action and use of circuit components
Core
•• Describe the action of a variable potential divider
(potentiometer)
•• Describe the action of thermistors and lightdependent
resistors and show understanding of
their use as input transducers
•• Describe the action of a relay and show
understanding of its use in switching circuits
Supplement
•• Describe the action of a diode and show
understanding of its use as a rectifier
•• Recognise and show understanding of circuits
operating as light-sensitive switches and
temperature-operated alarms (to include the use
of a relay)