A street lamp is switched on automatically when it gets dark. The circuit contains a light-dependent resistor (LDR) joined end to end with a fixed resistor and a switching unit. The switching unit turns the street lamp on when the current in the circuit falls below a set value.
Explain how the circuit switches the street lamp on as it gets dark.
The fixed resistor is replaced by one with a larger resistance. Explain the effect this has on the light level at which the street lamp switches on.
Give one advantage of using an LDR rather than a time switch to control the street lamp.