- Question A In Design Considerations Of A Power Amplifier State Any Three Factors That Are Considered As A Way To Preve 1 (57.65 KiB) Viewed 33 times
Question a) In design considerations of a power amplifier, state any three factors that are considered as a way to prevent thermal runaway. b) State any four advantages of electronic oscillators over mechanical oscillators. c) Qualitatively explain why most of electronic devices are not biased by an ac voltage. d) Explain why of recent batteries have been replaced by power supplies as de sources in electronic devices. e) A power transistor dissipates 8 W. If TJ max = 78°C, find the maximum ambient temperature at which it can be operated. Given thermal resistance 0 = 20°C/W. f) Explain why Zener diodes are used as voltage regulator. Illustrations speak volumes. g) Find the capacitance of the capacitor required to build an LC oscillator that uses an inductance of L1=1 mH to produce a sine wave of frequency 2 GHz. h) State any three factors that affect the heat sink as it transfers heat to the surrounding. Question a) Differentiate between a regulated and ordinary power supply. Illustrations carry more marks. b) Why are D.C power supplies preferred to batteries? c) wo power supplies A and B are available on the market. Power supply A has no-load and full load. voltages of 50 V and 35 V respectively whereas these values are 50 V and 46.5 V for supply B. Which is the better power supply and why? d) Describe the operation of a Zener voltage regulator. Explain how it encounters both line and load regulations. e) Explain the difference between the dual tracking IC regulator and the fixed negative IC regulator. f) With the aid of a diagram explain the working of the 7812 IC regulator stating its output voltage. g) Explain two reasons why there is a need for a regulated power supply.