Analog electronic difficult problem solving series (3): become a skilled electronic engineer
Electronic Fans News: We have brought you a summary of the series of difficult problems often encountered in analog e-learning: analog electronic problem solving series (1): How much do semiconductors and amplifiers know? (2): What you need to know about analog circuit design issues, today I brought you a series of three analog electronic problem solving puzzles for everyone to learn.
101. What is the most widely used power amplifier circuit?
Answer: The most widely used power amplifier circuits are OTL and OCL circuits.
102. What is crossover distortion?
Answer: Only when | Ui |> Uon, the triode is turned on. When the input signal Ui is before and after zero crossing, the output signal will appear distortion. This distortion is called crossover distortion.
103. How to eliminate crossover distortion?
Answer: In order to eliminate crossover distortion, an appropriate static operating point should be set so that both transistors work in the critical conduction or micro conduction state.
104. For the OCL power amplifier circuit, how to estimate the maximum output power of the circuit when the power supply voltage and load resistance are known?
Answer: The maximum output power of the OCL power amplifier circuit:
105. For the OCL power amplifier circuit, how to estimate the power provided by the power supply of the circuit when the power supply voltage and load resistance are known?
Answer: The power provided by the power supply of the OCL power amplifier circuit:
106. For an OTL power amplifier circuit, how to estimate the maximum output power of the circuit when the power supply voltage and load resistance are known?
Answer: The maximum output power of the OTL power amplifier circuit:
107. For the OTL power amplifier circuit, how to estimate the power provided by the power supply of the circuit when the power supply voltage and load resistance are known?
Answer: The power provided by the power supply of the OTL power amplifier circuit:
108. When choosing the transistor in the power amplifier circuit, what parameters should be paid special attention to?
Answer: When selecting the transistor in the power amplifier circuit, the parameters that should be paid special attention to are: the maximum tube voltage drop that the transistor can withstand, the maximum current of the collector and the maximum power consumption.
109. What is the maximum undistorted output voltage of the power amplifier circuit?
Answer: The maximum undistorted output voltage amplitude of the power amplifier circuit is equal to the power supply voltage minus the saturation voltage drop of the transistor, that is: Uom = Vcc-UCES.
110. What is the maximum output power of the power amplifier circuit?
Answer: The maximum output power of the power amplifier circuit refers to the maximum AC power that can be obtained on the load when the input voltage is a sine wave and the output is basically not distorted. That is: Pom = Uo & TImes; Io.
111. What is the conversion efficiency of the power amplifier circuit?
Answer: The conversion efficiency of the power amplifier circuit refers to the ratio of the maximum output power to the power provided by the power supply. That is: η = Pom / Pv.
112. Please briefly describe the steps to analyze the power amplifier circuit.
Answer: Because the input signal amplitude of the power amplifier circuit is large, the graphic method should be used in the analysis. Generally follow the steps below: (1) Find the amplitude of the AC voltage Uom that may be obtained on the load of the power amplifier circuit; (2) Find the maximum output power of the circuit Pom; (3) Find the average DC power Pv provided by the power supply; (4) Find the conversion efficiency η.
113. What is a breakdown of the power amplifier tube?
Answer: A breakdown of the power amplifier tube refers to the phenomenon that the collector current suddenly increases when the voltage between the CE of the transistor increases to a certain value.
114. What is the second breakdown of the power amplifier tube?
Answer: The second breakdown of the power amplifier tube refers to the phenomenon that when the transistor is broken once, if the collector current is not limited, the operating point of the transistor will change at a high speed, so that the current increases sharply and the tube voltage drop decreases.
115. How to choose a transistor in a power amplifier circuit?
Answer: When selecting the transistor, the limit parameters UCEO> 2Vcc; ICM> Vcc / RL; PCM> 0.2Pom.
116. When does the transistor dissipate the most power?
Answer: When Uom = 2Vcc / π≈0.6Vcc, PT = PTMAX, that is, the transistor dissipates the most power.
117. What is the zero drift phenomenon?
Answer: The phenomenon that the input voltage is zero and the output voltage is not zero and changes slowly is called the zero drift phenomenon.
118. What is temperature drift?
Answer: When the input voltage is zero, the phenomenon that the output voltage is not zero and changes slowly due to changes in semiconductor device parameters caused by temperature changes is called temperature drift. It causes the main cause of zero drift.
119. What are the methods to suppress zero drift?
Answer: The methods to suppress the zero drift are: (1) Introduce DC negative feedback in the circuit; (2) Adopt temperature compensation method, use thermal element to offset the change of the amplifier tube; (3) Use "differential amplifier circuit".
120. What are the special problems of the direct coupling amplifier circuit? How to solve?
Answer: The special problem of the direct coupling amplifier circuit is the existence of zero drift. The solution is to use a differential amplifier circuit.
121. What is the function of the differential amplifier circuit?
Answer: The differential amplifier circuit can amplify the differential mode signal and suppress the common mode signal.
122. What is the relationship between the common mode signal and zero drift and temperature drift?
Answer: Temperature drift is the main cause of zero drift, so generally speaking, zero drift refers to temperature drift. For the differential amplifier circuit, the temperature change is actually equivalent to a common-mode signal.
123. What are the characteristics of the circuit structure of the differential amplifier circuit?
Answer: The differential amplifier circuit consists of two transistors, and the parameters of all components in the circuit are symmetrical.
124. What is a differential mode signal?
Answer: The differential mode signal is the difference between the two input signals.
Bark Stop Collar,Best Bark Control,Remote Pet Training Collar,No Shock Bark Collar
Elite-tek Electronics Ltd , https://www.aetertek.ca