1 1.6 Op-Amp Basics Basic Op-Amp Op-amp equivalent circuit Practical (R i = high, R o = small)Ideal (R i =∞, R o = 0)

2 1.6 Op-Amp Basics Basic Operation of Op-Amp  input voltage at minus (-) output voltage opposite in phase  input voltage at plus (+) output voltage in phase Basic Op-Amp - Constant-gain multiplier  Input signal is applied through resistor R i to the minus input  Output is connected to the same minus input through resistor R f  Resulting output: opposite in phase to input signal Inverting constant gain multiplier

3 1.6 Op-Amp Basics Op-amp ac equivalent circuit Basic Op-Amp - Constant-gain multiplier

4 1.6 Op-Amp Basics Ideal Op-amp equivalent circuit Redrawn equivalent circuit (for circuit analysis) Basic Op-Amp - Constant-gain multiplier

5 1.6 Op-Amp Basics Using Superposition theorem Basic Op-Amp - Constant-gain multiplier i) V 1 only (set –A v V i =0) ii) –A v V i only (set V 1 =0)

6 1.6 Op-Amp Basics Basic Op-Amp - Constant-gain multiplier It is shown that the ratio i/o depends only on the value of R f and R 1

7 1.6 Op-Amp Basics Basic Op-Amp - Unity Gain If R f = R 1 Gain with negative sign shows that the output voltage has undergone 180º phase inversion from input signal Basic Op-Amp - Constant Gain If R f = 10R 1  If we select precise values for Rf and Ri, we can obtain a wide range of gains  Gain accuracy depends on resistors used  Gain is slightly affected by temperature & other circuit factors

8 1.7 Practical Op Amp Circuits Inverting Amplifier Non-inverting Amplifier Inverting constant gain multiplierNon-inverting constant gain multiplier

9 1.7 Practical Op Amp Circuits Non-inverting Amplifier Equivalent circuitNon-inverting constant-gain multiplier Which results in; Since V i = 0, using voltage divider rule,

Data Sheet LM741

Data Sheet LM741 ABSOLUTE MAXIMUM RATINGS  Supply voltage = +22V  Internal power dissipation = 500mW  Differential input voltage = + 30V  Input voltage = + 15V ELECTRICAL CHARACTERISTICS  Input offset voltage  Input offset current  Input bias current  Input resistance

Data Sheet LM741 ELECTRICAL CHARACTERISTICS  Large signal voltage gain  Output voltage swing  Output short circuit current  Supply voltage rejection ratio  Bandwidth  Slew rate  Supply current  Power consumption

Data Sheet LM741

Data Sheet LM741

Data Sheet LM741