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Basic ELECTRONICS
(2+1)ENGR MUHAMMAD SHAKEEL AKRAM
ELECTRONICS ENGINEERING FICT, BUITEMS.
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CHAPTER 6
BJT AMPLIFIERS
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COMMON EMITTER AMPLIFIERS• Most commonly used amplifier• High voltage gain• High current gain • 180˚ out of phase
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COMMON EMITTER AMPLIFIERS• DC analysis
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COMMON EMITTER AMPLIFIERS• AC analysis
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COMMON EMITTER AMPLIFIERS• AC analysis (cont…)
• Voltage at base
• Input resistance at base
• Output resistance
Example
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COMMON EMITTER AMPLIFIERS• AC analysis (cont…)
• Voltage gain
• Current gain
• Power gain
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COMMON COLLECTOR AMPLIFIERS• Also called emitter follower• High input resistance• High current gain • Voltage gain is equal to one• Power gain is nearly equal to current gain• No phase inversion • High input resistance• Low output resistance
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COMMON BASE AMPLIFIERS
• High voltage gain• Current gain equal to one• So power gain becomes nearly equal to
voltage gain• Low input resistance• High output resistance
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COMPARISON OF AMPLIFIERS
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