an electrical component that is used to prevent current flow in one direction

a material that has both metallic and non-metallic properties

the potential difference at which a diode allows current to flow

when a diode is reverse–biased, it prevents current from flowing

when a diode is forward–biased, it allows current to flow

Measuring the resistance of a diode

Combined science

Measuring the resistance of a filament lamp

Resistance of a hot metal

Interpreting I–V graphs

Potential divider circuits

LDRs and thermistors

In the Mains electricity unit, they will build on this knowledge to learn about the dangers of mains electricity, how to use mains electricity safely, the equations I=Q/t, V=E/Q and P=IV, and about the transmission of power in the national grid, including transformers.

In the Electric fields and circuit calculations unit, pupils learnt about the properties of electric fields, moving electric charge, and how to analyse series and parallel electrical circuits.

This unit explores current, resistance, and potential difference. It covers circuit design for lamps, diodes, and thermistors, and emphasises planning experiments, data interpretation, and presenting scientific conclusions.

Circuit components

Physical activity and equipment requiring safe use

Which of the following components are shown in the image?

there is one positive and one negative end

Which of the following statements about the ends of a diode is correct?

Which of the following are the main chemical elements that can be used to make diodes?

What type of voltmeter is needed to measure the potential difference (p.d.) across a diode: one that measures in volts (V), millivolts (mV), or kilovolts (kV)?

When the positive end of a diode is connected to the positive terminal of a battery and the negative end of the diode is connected to the negative terminal of the battery, the diode is ...

Which of the following occurs when the p.d. across a forward–biased diode is increased to just above the threshold p.d.?

What happens when free electrons in a metal collide with metal ions?

What causes free electrons in a metal to move?

the metal ions will vibrate less vigorously

Which of the following effects will result from a higher p.d. across a metal wire in a working electrical circuit?

resistor A has a higher resistance than resistor B

resistor A has a lower resistance than resistor B

it is not possible to say which resistor has the higher resistance

Which of the followings statements about resistors A and B is correct?

Which of the following elements is a semiconductor?

as the p.d. increases, the resistance increases

as the p.d. increases, the resistance decreases

the resistance remains the same as the p.d. changes

it is not possible to say if the resistance changes

Which of the following statements about the I–V graph shown is correct?

Measuring the resistance of a diode

Lesson outcome

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