Physics 9702 · AS & A Level · Rectification and smoothing

Rectification and smoothing — practice question

A student builds an electronic sensor intended to turn on a lamp whenever the light intensity is low. The circuit is partly shown in Fig. 10.1.
(a)[1]

State the name of the component marked X in Fig. 10.1.

(b(i))[2]

On Fig. 10.1, add the symbols for two resistors to finish the sensing-device circuit.

(b(ii))[2]

On Fig. 10.1, add the relay symbol to complete the processing-unit circuit.

(c(i))[1]

State the purpose of the relay.

(c(ii))[2]

Suggest why the diode is connected to the output of the operational amplifier (op-amp) in the direction shown.

Worked solution & mark scheme

This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: LDR (light-dependent resistor)

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