Figure 1 shows the basic layout for a Johnson decade counter - AQA - A-Level Physics - Question 1 - 2019 - Paper 8
Question 1
Figure 1 shows the basic layout for a Johnson decade counter. The main outputs are shown as Q0 to Q9.
Figure 2 shows part of the timing diagram for a Johnson decade... show full transcript
Worked Solution & Example Answer:Figure 1 shows the basic layout for a Johnson decade counter - AQA - A-Level Physics - Question 1 - 2019 - Paper 8
Step 1
Complete Figure 2 to show the logic states of Q0
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Answer
Q0 will remain high (1) for the duration of the first clock pulse. Thus, the logic state of Q0 is a flat line at logic high during this period.
Step 2
Complete Figure 2 to show the logic states of Q1
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Answer
Q1 will change state (low to high) as the first clock pulse ends, resulting in Q1 rising to high (1) on the first clock transition.
Step 3
Complete Figure 2 to show the logic states of Q2
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Answer
Q2 remains low (0) until Q1 transitions to high (1). It will change to high (1) only when Q1 is at high for the clock period.
