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Refer to FIGURE 5.11 below and answer the questions that follow - NSC Electrical Technology Electronics - Question 5 - 2019 - Paper 1
Question 5
Refer to FIGURE 5.11 below and answer the questions that follow. 5.11.1 Identify the circuit diagram in FIGURE 5.11. 5.11.2 Explain how cross-over distortion is el... show full transcript
Worked Solution & Example Answer:Refer to FIGURE 5.11 below and answer the questions that follow - NSC Electrical Technology Electronics - Question 5 - 2019 - Paper 1
Step 1
Step 2
5.11.2 Explain how cross-over distortion is eliminated in this amplifier.
Answer
Cross-over distortion is eliminated in a complementary push-pull amplifier by maintaining a small biasing current through each transistor in the output stage. This ensures that both transistors remain slightly turned on even when there is no input signal, which prevents the distortion that typically occurs during the transition between the positive and negative halves of the output waveform.
Step 3
5.11.3 State the purpose of the resistors in the circuit diagram.
Answer
The resistors in the circuit diagram serve multiple purposes:
- They help set the biasing conditions of the transistors, ensuring they operate in their linear region.
- They provide stability against variations in transistor beta (current gain), enhancing overall circuit performance.
- They also aid in controlling the gain of the amplifier by defining the feedback levels.
Step 4
5.11.4 Draw a fully labelled output waveform of the circuit diagram on the ANSWER SHEET for QUESTION 5.11.4.
Answer
The output waveform for a complementary push-pull amplifier reveals two distinct sections corresponding to the positive and negative halves of the input signal. The waveform should show minimal distortion around the zero-crossing point, illustrating a smooth transition as the output approaches both the maximum and minimum amplitudes. Ensure to label key points indicating the positive and negative swings.