Learning Objectives (стр. 5 )

Save your circuit as “E1-Circuits2-Act10”

Homework Questions 2:

Answer all questions in the spaces provided; continue on a separate piece of paper if required.

1. You have been given a 6V, 0.06A bulb and told to connect it to a 12V supply.

i) What will be the result if you carried out this instruction?

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ii) How could you carry out the instruction successfully?

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2. Resistors can be used to split the voltage from a battery into smaller voltages for use in other parts of the circuit. This application is called a potential divider. Draw two circuit diagrams to show how a 10kΩ and 5kΩ resistor can be used to provide output voltages of (i) 4V and (ii) 8V from a 12V power supply.

i) ii)

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3. A 100Ω resistor has a current of 100mA flowing through it when the voltage across it is 10V. Calculate the power dissipated in the resistor.

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4. A 220Ω resistor has a current of 10mA flowing through it. Calculate the power dissipated in the resistor.

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5. Give two advantages and two disadvantages of Wire wound resistors.

Advantages:

i) ...................................................................................................................

ii) ...................................................................................................................

Disadvantages:

i) ...................................................................................................................

ii) ...................................................................................................................

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6. Give two advantages and one disadvantage of Carbon Film resistors.

Advantages:

i) ...................................................................................................................

ii) ...................................................................................................................

Disadvantage:

i) ...................................................................................................................

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7. When trying to select a resistor for a particular application, there are three critical parameters or properties of the resistor that need to be considered. What are they?

i) ...................................................................................................................

ii) ...................................................................................................................

iii) ...................................................................................................................

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8. i) A resistor is marked with the following coloured bands, Red, Red, Brown, Gold. What is its value and tolerance?

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ii) A resistor is marked with the following coloured bands, White, Brown, Red, Silver. What is its value and tolerance?

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iii) A resistor is marked with the following coloured bands, Brown, Black, Orange, Gold. What is its value and tolerance?

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iv) A resistor is marked with the following coloured bands, Blue, Grey, Black, Gold. What is its value and tolerance?

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9. i) What would be the colour of the bands on a 4.7kΩ ± 10% resistor?

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ii) What would be the colour of the bands on a 100kΩ ± 5% resistor?

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iii) What would be the colour of the bands on a 33kΩ ± 20% resistor?

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iv) What would be the colour of the bands on a 39Ω ± 5% resistor?

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10. i) A resistor is stamped with the number 47R. What is its value in ohms?

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ii) A resistor is stamped with the number 2k7. What is its value in ohms?

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iii) A resistor is stamped with the number 1M. What is its value in ohms?

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11. Using the printed value method of marking resistors, what would you see marked on the following resistors.

i) 10,000 Ω .......................................

ii) 3,300 Ω .......................................

iii) 5,600,000 Ω .......................................

iv) 10 Ω .......................................

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12. A 3.5V 0.03A bulb is to be run from a 9V power supply. A resistor must be used to limit the current flowing in the circuit.

i) Draw a diagram of the circuit required.

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ii) Calculate the exact value of the resistor required to limit the current in the circuit.

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iii) What value of resistor would you choose from the E24 series of resistors to use in your circuit. Give a reason for your choice.

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13. A resistor has a value of 1kΩ ±5%. Calculate the minimum and maximum value of resistance that this resistor may have.

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14. Calculate the voltage at the output terminals in each of the following circuits.

i)

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ii)

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iii)

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