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Operation amplifier: Symbol, Example, Characteristics, Structure, Operation, Applications. Characters of circuits depend on outside circuit structure, not the opamp itself, Gain AV: very high, ideally ∞, Zin: very large, ideally ∞, Zout: very small, ideally 0. | Operation amplifier Symbol Example Characteristics Structure Operation Applications μp 741 Symbol Example Characteristics Characters of circuits depend on outside circuit structure, not the opamp itself Gain AV: very high, ideally ∞ Zin: very large, ideally ∞ Zout: very small, ideally 0 Current entering the amp at either terminal: extremely small, ideally 0 Voltage out (when voltages into each other are equal): small, ideally 0 Bandwidth: broad, ideally infinite Characteristics Input: 2 inputs (positive and negative) Single-ended input: 1 input to signal source, 1 input to ground Double-ended input: 2 different signal sources or 1 signal source apply between 2 inputs Output: 1 or 2 outputs, typically 1 output Mode gain: Differential-mode gain Adm - large Common-mode gain Acm - small Common-mode rejection ratio CMRR=G=Adm/Acm, usually about 103-105 Structure Requirement: Gain: large Offset: small Currents: small Input impedance: large Output impedance: small Input: symmetric Structure | Operation amplifier Symbol Example Characteristics Structure Operation Applications μp 741 Symbol Example Characteristics Characters of circuits depend on outside circuit structure, not the opamp itself Gain AV: very high, ideally ∞ Zin: very large, ideally ∞ Zout: very small, ideally 0 Current entering the amp at either terminal: extremely small, ideally 0 Voltage out (when voltages into each other are equal): small, ideally 0 Bandwidth: broad, ideally infinite Characteristics Input: 2 inputs (positive and negative) Single-ended input: 1 input to signal source, 1 input to ground Double-ended input: 2 different signal sources or 1 signal source apply between 2 inputs Output: 1 or 2 outputs, typically 1 output Mode gain: Differential-mode gain Adm - large Common-mode gain Acm - small Common-mode rejection ratio CMRR=G=Adm/Acm, usually about 103-105 Structure Requirement: Gain: large Offset: small Currents: small Input impedance: large Output impedance: small Input: symmetric Structure Input stage Intermediate stage Level shifting stage Output stage Example: 741 – at the end of chapter Applications Basic and advance applications Basic applications: Inverting, non-inverting amplifier Uni-gain circuit Addition and subtraction circuits Integration and differential circuits Multi-stages circuit Applications Advance applications Current-controlled voltage source Voltage-controlled current source DC voltmeter AC voltmeter Driver circuit Active filters NIC .etc. Non-inverting fixed-gain amplifier Prove: V- = V+ = V1 I- = I+ = 0 =>IR1 = Irf = V1/R1 =>A = 1+Rf/R1 Non-inverting fixed-gain amplifier A = 1+Rf/R1=101 Vo=101Vi Inverting fixed-gain amplifier Prove: V- = V+ = 0 I- = I+ = 0 =>IR1 = Irf = V1/R1 =>A = -Rf/R1 Voltage addition Vo = -V1Rf/R1-V2Rf/R2 –V3Rf/R3 If V1=V2=V3 then: A= -Rf/R1-Rf/R2 –Rf/R3 Voltage subtraction Vout1 = -Rf/R1V1 Vout = -Rf/R2V2 - Rf/R2Vout1 = -Rf/R2V2 + Rf/R2V1 = -Rf/R2(V1 – V2) Voltage subtraction with 1 amp Prove: V-=V+=V1*R3/(R1+R3) I- = I+ = 0 .
