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3 marksLogic Gates

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

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).

Find the logic combination that causes the alarm to sound by determining the outputs at A, B and C in Figure 6.

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Other parts of this question

  1. 5(a)(i)State the name of EACH logic gate represented below.[1 mark]
  2. 5(a)(ii)State the name of EACH logic gate represented below.[1 mark]
  3. 5(a)(iii)State the name of EACH logic gate represented below.[1 mark]
  4. 5(b)(i)Complete the truth tables for the NOT and NOR gates.[1 mark]
  5. 5(b)(ii)Complete the truth tables for the NOT and NOR gates.[2 marks]
  6. 5(c)(ii)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.[3 marks]
  7. 5(d)(i)State THREE ways in which advances in electronics, such as the introduction of logic gates, have made a positive impact on society.[3 marks]
  8. 5(d)(ii)State THREE ways in which advances in electronics, such as the introduction of logic gates, have made a positive impact on society.[1 mark]
  9. 5(d)(iii)State THREE ways in which advances in electronics, such as the introduction of logic gates, have made a positive impact on society.[1 mark]

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