4.1 Name ONE mode of operation of the metal-oxide-semiconductor field-effect transistor (MOSFET) - NSC Electrical Technology Electronics - Question 4 - 2021 - Paper 1
Question 4
4.1 Name ONE mode of operation of the metal-oxide-semiconductor field-effect transistor (MOSFET).
4.2 Refer to FIGURE 4.2 below and answer the questions that follow... show full transcript
Worked Solution & Example Answer:4.1 Name ONE mode of operation of the metal-oxide-semiconductor field-effect transistor (MOSFET) - NSC Electrical Technology Electronics - Question 4 - 2021 - Paper 1
Step 1
4.1 Name ONE mode of operation of the metal-oxide-semiconductor field-effect transistor (MOSFET).
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Answer
The mode of operation can be either Enhancement mode or Depletion mode.
Step 2
4.2.1 Identify the semiconductor symbol in FIGURE 4.2.
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Answer
The symbol for a MOSFET consists of a gate, drain, and source with a specific representation for each.
Step 3
4.2.2 Explain how the metal-oxide-semiconductor field-effect transistor (MOSFET) differs from the junction field-effect transistor (JFET) with reference to its construction.
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The MOSFET has an insulating oxide layer between the gate and the channel, while JFETs have the gate and channel physically connected.
Step 4
4.3.1 Identify puls B2.
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Puls B2 is identified as a sawtooth waveform.
Step 5
4.3.2 Explain the term saturation region with reference to the operation of the UJT.
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Saturation is the state when the emitter is sufficiently forward biased, causing the UJT to conduct maximally.
Step 6
4.3.3 Describe how the UJT is driven into the CUT-OFF mode.
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The UJT enters CUT-OFF when the voltage across the capacitor resets the emitter to a high resistance state.
Step 7
4.4.1 Identify the circuit diagram in FIGURE 4.4.
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Answer
The circuit diagram is identified as a Darlington transistor amplifier.
Step 8
4.4.2 Describe how the transistors are biased and fully turned ON by referring to the required voltages.
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When a voltage exceeding 1.4 V is applied to the base of the Darlington transistor, it is fully turned ON.
Step 9
4.4.3 State TWO advantages of the circuit in FIGURE 4.4.
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Provides high current gain. 2. Improves input impedance.
Step 10
4.4.4 Explain why the transistor in FIGURE 4.4 is preferred over a single transistor when used as a switch.
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A Darlington configuration provides higher current amplification, making it suitable for loads requiring more current.
Step 11
4.5.1 Identify the type of operational amplifier in FIGURE 4.5.
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The operational amplifier is a Non-Inverting Operational Amplifier.
Step 12
4.5.2 Draw the output voltage waveform on the ANSWER SHEET for QUESTION 4.5.2.
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The output waveform follows the input waveform, showing amplified variations.
Step 13
4.5.3 Explain why operational amplifiers are known as differential voltage amplifiers.
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They amplify the difference in voltage between two inputs, allowing for accurate signal processing.
Step 14
4.6.1 Explain the function of the RS flip-flop.
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The RS flip-flop stores binary information and changes states based on input triggers.
Step 15
4.6.2 State the typical operating voltage range of the 555 IC.
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The typical operating voltage range of the 555 IC is from +5 V to +15 V or +18 V.
Step 16
4.6.3 Name TWO modes of operation for the 555 IC.
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Astable mode. 2. Monostable mode.
Step 17
4.6.5 Explain the function of the threshold input on Pin 6 of a 555 timer IC.
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It monitors the voltage at which the IC will reset if exceeded.
Step 18
4.7 Refer to FIGURE 4.7 below and explain why the output is zero volts.
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When both inputs are equal, the output cancels out, resulting in an output of zero volts.
Step 19
4.8.1 Calculate the output voltage.
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Using the formula:
V_{out} = rac{V_{in} imes R_f}{R_n}
The output voltage is calculated to be 127.5 mV.
Step 20
4.8.2 Explain the effect on the output when the value of the feedback resistor is equal to that of the input resistor.
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The output voltage will be double the input voltage when feedback resistance equals input resistance.
