EE 332 Lecture 22 2019.pdf - EE 332 Devices and Circuits II Lecture#22 ©UWECE TC Chen CE AMPLIFIER(INVERTING WITHOUT BYPASS CAPACITOR/SMALL SIGNAL

EE 332 Lecture 22 2019.pdf - EE 332 Devices and Circuits II...

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5/8/2019 1 ©UWECE TC Chen EE 332: Devices and Circuits II Lecture #22 ©UWECE TC Chen CE AMPLIFIER (INVERTING) WITHOUT BYPASS CAPACITOR/ SMALL SIGNAL MODEL R I v I C1 R 2 R 1 R C R E Q1 C3 V CC R 3 v o v o v i R B R C R 3 r r o g m v be v be R I R E
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5/8/2019 2 ©UWECE TC Chen CE AMPLIFIER (INVERTING) WITHOUT BYPASS CAPACITOR/ INPUT RESISTANCE v o v i R B R C R 3 r r o g m v be v be R I R E + R iB R in v x Dead network impedance Test source i x R iB R E r i x i e =( +1)i x Input resistance: ? 𝑖? ?? = ? 1 ∥ ? 2 ∥ ? 𝑖? Apply KVL from test voltage to emitter: 𝑣 𝑥 = 𝑖 𝑥 𝑟 𝜋 + 𝑖 𝑥 𝛽 + 1 ? ? ? 𝑖? = 𝑣 𝑥 𝑖 𝑥 = 𝑟 𝜋 + 𝛽 + 1 ? ? Higher resistance than ? 𝐸 = 0 ©UWECE TC Chen CE AMPLIFIER (INVERTING) WITHOUT BYPASS CAPACITOR/ OUTPUT RESISTANCE v o v i R B R C R 3 r r o g m v be v be R I R E R iB R in Output resistance: ? ??? ?? = ? ? ∥ ? 𝑖? Applying voltage division from base to emitter: 𝑣 𝑏 = 𝑣 𝑒 ? ?ℎ ? ?ℎ + 𝑟 𝜋 𝑣 𝑏 − 𝑣 𝑒 = 𝑣 𝑏𝑒 = −𝑣 𝑒 𝑟 𝜋 ? ?ℎ + 𝑟 𝜋 R iC R o v be R th v x R E r R iC g m v be r o i c v e v b
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