Complete Table 1 to show the logic outputs for the lamps L1 and L6 - AQA - A-Level Physics - Question 2 - 2017 - Paper 8
Question 2
Complete Table 1 to show the logic outputs for the lamps L1 and L6.
| Number shown on die | Logic inputs | Logic outputs |
|---------------------|--------------|---... show full transcript
Worked Solution & Example Answer:Complete Table 1 to show the logic outputs for the lamps L1 and L6 - AQA - A-Level Physics - Question 2 - 2017 - Paper 8
Step 1
Complete Table 1 to show the logic outputs for the lamps L1 and L6.
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Answer
Number shown on die
Logic inputs
Logic outputs
B
A
1
0
0
2
0
1
3
1
0
4
1
1
5
1
1
6
0
1
Reset 6 -> 1
0
0
Step 2
Deduce the simplest Boolean expression that can be used to show how output L7 can be controlled by the logic inputs.
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Answer
The simplest Boolean expression for L7 can be described as:
L7=¬A
This implies L7 is ON when A is OFF.
Step 3
Draw on Figure 6 the logic gate needed and the connections required from the outputs to the reset pin R on the counter so that the counter cycles as required.
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Answer
To connect the reset pin R properly, attach it to the output conditions from B and C using an AND gate. The output from the AND gate will drive the reset pin to logic 1 when both inputs are 1, ensuring proper reset conditions for the counter.
Step 4
The output of both L3 and L4 can be written as (A . B . C) + (B . C).
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Answer
To represent the logic circuit, we can use AND gates for the terms A . B . C and B . C to create the output combining them with an OR gate. This configuration ensures that L3 and L4 light up based on the specified conditions based on the input logic states.
