CSEC Physics · January 2017 · Paper 2 · Question 5(c)(ii)

Figure 5 shows a basic home security system that provides protection for two windows and front and back doors. The use of OR gates facilitates the system with all inputs on Low (0). If a disturbance occurs the input turns to High (1). The alarm will sound only if a High (1) output is received. Figure 6 shows an intruder at Window 2 causing its input to change to High (1).

If a simultaneous disturbance is triggered at the back door and at Window 2, show on Figure 7, the logic output at A, B and C.

This question uses a figure or table from the paper — you'll see it when you practise.