IB Design Technology Topic B3.4: Electronic Systems Application and Selection Questionbank

A home appliance company is designing an automatic bathroom light system that turns on when someone enters, dims based on ambient light, and switches off after a set time delay using a basic logic circuit.

A design team is developing a smart agricultural monitoring system to maintain crop health in remote greenhouses. The system uses sensors, control logic, and actuators to detect environmental changes and respond automatically.

What type of circuit configuration allows current to split across multiple paths?

The smart thermostat in Figure 1 controls a domestic heating system. The user sets a target temperature, shown here as 20 degrees Celsius, and the thermostat then holds the room at that temperature on its own. A sensor reads the room temperature, the thermostat compares that reading with the target, and the boiler is switched on or off in response. The reading is taken continuously, so the system keeps correcting itself as the room warms up or cools down.

Figure 1: Smart thermostat, showing a target temperature of 20 on its display

Lumire Cycles manufactures the LED bicycle lamp shown in Figure 2. Inside the lamp, a 6 V battery drives a driver circuit containing three resistors connected in series, of 10 ohms, 20 ohms and 30 ohms, which limit the current reaching the LED. The rider switches the lamp on with the button on the top of the housing.

Figure 2: LED bicycle lamp mounted on the handlebar, showing the lens and the switch on top of the housing