Name:......
Tasks:
Start by working through pages 25 and 26 in your workbook! USE 6V ONLY when conducting these tests.
You are now required to check the current in your circuit. This will require you to break part of your circuit.
Explain how and where you did this, and write down the value you have for the current.
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555 Timer, connected to the 4026 driving the 7 Segment Display
Using your existing 555 timer circuit,connect the counter part of the circuit (the 4026 chip and the seven segment display)
Task:
1)Are the chips is inserted the correct way round if unsure please ask. How do you know it is the right way around?
2)Use the logic probe to check what is happening at pin 3 of the 555 timer. What is happening? Explain why.
3)Move the logic probe to pin 1 of the 4026 chip. What is happening here? Use you workbook to help by looking at page 26.
4)Would you expect pin 3 of the 4026 to be HI or LOW? Explain why.
5)Check you have the correct output state at pin 8 and 16. What should they be?
Go round each of the output pins on the 4026 with your logic probe and check that each is on and the correct segment of the display is working. If a segment of the display is not working or is incorrect then check each of your connections.YOU MAY NEED TO SWITCH THE PROBE TO TTL IF YOU DONT GET THE EXPECTED OUTPUT
6)Look at the table on page 26. This shows the segments needed for each count from 0 to 9. Can you think of any other numbers/characters you could produce? Fill in the following table if you can. Add any more you can think of!
Outputs from the 4026 counter and display driver ICCount / a / b / c / d / e / f / g
1
2
A
C
4
E
F
7)Check the action of the reset switch. If it does not function use your logic probe to find out why.
Board A
Board A is the standard 555 Timer which you have already constructed. Use the test and checks we have discussed to find any problems with it. Use the space provided below to describe your findings and draw any diagrams.
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Board B
Board B is the standard 555 Timer which you have already constructed. Use the test and checks we have discussed to find any problems with it. Use the space provided below to describe your findings and draw any diagrams.
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Board C
Board C is the standard 555 Timer which you have already constructed. Use the test and checks we have discussed to find any problems with it. Use the space provided below to describe your findings and draw any diagrams.
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Board D
Board D is the standard 555 Timer which you have already constructed. Use the test and checks we have discussed to find any problems with it. Use the space provided below to describe your findings and draw any diagrams.
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Unit 5 –Electrical and Electronic Circuits and Systems