draw circuit diagrams with power sources (cell, battery, d.c. supply or a.c. supply), switches, lamps, resistors (fixed and variable), variable potential divider (potentiometer), fuses, ammeters and voltmeters, bells, light-dependent resistors, thermistors and light-emitting diodes

state that the current at every point in a series circuit is the same and apply the principle to new situations or to solve related problems

state that the sum of the potential differences in a series circuit is equal to the potential difference across the whole circuit and apply the principle to new situations or to solve related problems

state that the current from the source is the sum of the currents in the separate branches of a parallel circuit and apply the principle to new situations or to solve related problems

state that the potential difference across the separate branches of a parallel circuit is the same and apply the principle to new situations or to solve related problems

recall and apply the formulae for the effective resistance of a number of resistors in series and in parallel to new situations or to solve related problems

recall and apply the relevant relationships, including R = V / I and those for current, potential differences and resistors in series and in parallel circuits, in calculations involving a whole circuit

describe the action of a variable potential divider (potentiometer)

describe the action of negative temperature coefficient (NTC) thermistors and light-dependent resistors and explain their use as input transducers in potential dividers

solve simple circuit problems involving NTC thermistors and light-dependent resistors.

the sum of individual currents in each of the branches is equal to the main current.

I_ε = I₁ + I₂ + I₃ + … + I_n

the potential difference across each branch is equal to the potential difference across the whole circuit.

Vε = V₁ = V₂

In a parallel circuit, the effective resistance is always smaller than the smallest individual resistance.

the current at every point is the same;

the sum of the potential difference across each component is equal to the potential difference across the whole circuit.

V_ε = V₁ + V₂ + V₃ + … + V_n

R_T = R₁ + R₂ + . . . + R_n

As we have seen, we can vary the value of V_out by changing the resistance of the resistors R₁ and R_2..

To do this, we can change the fixed resistors, or we can make use of variable resistors.

Transducers are electronic devices that convert energy from one form to another.

They are two types: input transducers and output transducers.

Input transducers are electronic devices that respond to changes in the physical environment.

They can be used in potential dividers to vary output voltages.

Therefore, they allow electronic devices to respond to changes in the environment.

Input transducers are electronic devices that convert non-electrical energy to electrical energy.