Rayat Shikshan Sansthas S M Joshi College Hadapsar028

Rayat Shikshan Sanstha’s S. M. Joshi College Hadapsar-028 Department of Electronics Science Operational amplifier Presented by. Dr. Kakade K. P

The operational amplifier or op-amp is a circuit of components integrated into one chip. A typical op-amp is powered by two dc voltages and has an inverting(-) and a non-inverting input (+) and an output. An op amp is an electronic device which provides a voltage output based on the voltage input introduction

Basic op-amp introduction

Operational Amplifiers Five important pins ◦ ◦ ◦ 2 3 6 4 7 – – – The The The inverting input non-inverting input output negative power supply V- (-Vcc) positive power supply V+ (+Vcc) introduction

Operational Amplifiers � The output of the op amp is given by the following equation: Vd = E 1 – E 2 and Vo = AVOL(Vd) is called the open-loop voltage gain because it is the gain of the op amp without any external feedback from output to input � AVOL introduction

Operational Amplifiers Positive Saturation – where the output voltage exceeds the positive power input introduction

Operational Amplifiers Linear Region – where the output voltage is linear based on A (gain) introduction

Operational Amplifiers Negative Saturation – where the output voltage would be less than the negative power input introduction

Operational Amplifiers introduction

What do they really look like? introduction

IC Circuit introduction

Operational Amplifiers introduction

Operational Amplifiers ØAn ideal op-amp has infinite gain and bandwidth, we know this is impossible. ØHowever, op-amps do have: Øvery high gain Øvery high input impedance(Zin = ∞) Øvery low output impedance (Zout = 0) Øwide bandwidth. introduction

Application in op-amp � There are 2 types of application in op-amp ◦ Linear application ◦ Non-linear application � Linear application is where the op-amp operate in linear region: ◦ Assumptions in linear application: �Input current, Ii = 0 �Input voltage: V+=V�Feedback at the inverting input application

Application in op-amp � Non-linear application is where the op-amp operate in non-linear region � By comparing these two input voltages: positive input voltages, V+ and negative input voltage, V- where: VO = VCC if V+ > VVO = -VEE if V+ < V� Input current, Ii = 0 application

Applications of op-amp ◦ ◦ ◦ Comparator Inverter Audio amplifier Difference Amplifier Filter Summing Amplifier application

Op-amp Circuit Application � Inverting Amplifier � Non-Inverting Amplifier � Summing Amplifier � Unity Follower � Difference Amplifier � Integrators � Differentiators application

Application: Inverting amplifier ¡ ¡ ¡ Provide a constant gain multiplier Input signal is connected to the inverting input of the opamp. Therefore, the output signal is 180 degree out of phase from the input signal Rf is the feed-back resistor to control the voltage gain of the op-amp application: inverting amplifier

Summary of op-amp behavior Vo = A(V+ - V ) Vo/A = V+ - V Let A infinity then, V+ - V application: inverting amplifier 0

Summary of op-amp behavior V+ = V I+ = I = 0 Seems strange, but the input terminals to an op-amp act as a short and open at the same time application: inverting amplifier

To analyze an op-amp circuit for linear operation • Write node equations at + and - terminals (Ii=I+ = I- = 0) • Set V+ = V • Solve for Vo application: inverting amplifier

Analysis of inverting amplifier If I 1 Ii application: inverting amplifier

Application: Non-inverting amplifier application: non-inverting amplifier

Non-inverting configuration I 2 I 1 Vi Ii

Application: Summing amplifier introduction

Summing Amplifier Rf V 1 V 2 R 1 R 2 R 3 V 3 This circuit is called a weighted summer

Application: Unity Follower application: unity-follower

Application: Difference amplifier introduction

Application: Instrumentation Amplifier Buffer (Penimbal) Difference amplifier introduction

Application: Integrator I IC introduction

Application: Differentiation application: differentiator

Exercise 1 Find VO? exercise

Exercise 2 Find V 2 and V 3? exercise

Exercise 3 Find VO? exercise

Exercise 4 Find VO? exercise

Recall: Non-linear application in op-amp � Non-linear application is where the op-amp operate in non-linear region � By comparing these two input voltages: positive input voltages, V+ and negative input voltage, V- where: VO = VCC if V+ > VVO = -VCC if V+ < V� Input current, Ii = 0 non-linear application

Non-linear application: Comparator (Pembanding) non-linear application: comparator

Non-linear application: Comparator (Pembanding) (a) Input Voltage of Comparator VS(V) t Compare V+ and VV+=0 V-=VS When: VS>0, V+>VVS<0, V+<V- Vo(V) 10 t so Vo=10 V so Vo=-5 V -5 (b) Output Voltage of Comparator non-linear application: comparator

Non-linear application Schmitt Trigger (Pemicu Schmitt) Positive Feedback - + non-linear application: schmitt trigger

Non-linear application Schmitt Trigger (Pemicu Schmitt) VS(V) (b) Input Voltage of Schmitt Trigger 7. 5 t -7. 5 (a) Transfer Characteristic of Schmitt Trigger Vo(V) 15 15 -10 -7. 5 -15 10 VS(V) t -15 (c) Output Voltage of Schmitt Trigger non-linear application: schmitt trigger