1. What is an Op-Amp Low cost integrating circuit consisting of:
Transistors
Resistors
Capacitors
Able to amplify a signal due to an external power supply
Name derives from its use to perform operations on a signal.

2. Applications of Op-Amps
Simple Amplifiers
Summers
Comparators
Integrators
Differentiators
Active Filters
Analog to Digital Converters

3. Symbol for an Op-Amp +V Inverting Input Terminal
Non-Inverting Input Terminal

4. IC Circuit

5. What do they really look like?

6. Ideal Op-Amps Infinite input impedance Infinite gainV-
Vout I+ V+
Infinite input impedance
I+ = I- = 0
Infinite gain
V+ = V-
Zero output impedance
Output voltage is independent of output current

7. Inverting Amplifier R RF
Vin
iin
iout C

8. Non-Inverting AmplifierRF
iin
iout C
Vin

9. Summing Circuits Used to add analog signals
Voltage averaging function into summing function
Calculate closed loop gain for each input
If all resistors are equal in value:

10. Difference Circuit Used to subtract analog signals
Output signal is proportional to difference between two inputs
If all resistors are equal:

11. Integrating Circuit
Replace feedback resistor of inverting op-amp with capacitor
A constant input signal generates a certain rate of change in output voltage
Smoothes signals over time

12. Differentiating Circuit
Input resistor of inverting op-amp is replaced with a capacitor
Signal processing method which accentuates noise over time
Output signal is scaled derivative of input signal

13. Filters
Low Pass Filters
High Pass Filters
Band Pass Filters

14. Low Pass Filter Used to filter out signals above a specified frequency
Example: Noise
Frequency range is governed by:
Where
R = R2
C = C2

15. High Pass Filter Filters out frequencies below a specified frequency
Reverse locations of resistors and capacitors in a low pass filter

16. Band Pass Filter Created by combining a high and low pass filter
Only allows signals within frequency ranges specified by the low and high pass filters to pass

17. Comparator Circuit V1 is Vref V2 is Vin
Determines if one signal is bigger than another
No negative feedback, infinite gain and circuit saturates
Saturation: output is most positive or most negative value

18. OR Gate
If U1 or/and U2 = 5V,
U3 = 5V
If U2 and U1 = 0V,
U3 = 0V

19. Offset Comparator If
U3 = 0V
U3 = 5V

20. Real Vs Ideal Op Amp Parameters Ideal Typical Input Impedance ∞ 106Ω
Output Impedance 0Ω Ω
Voltage Gain
Common Mode voltage
10-5

21. Non-Ideal Op-Amps Gain Bandwidth Falloff Frequency Slew Rate (ΔV/ΔT)
Rise Time

22. Gain Bandwidth
Gain Bandwidth Product (GBP)- is the product of the open-loop gain and the bandwidth at that gain.
For practical purposes the actual gain should only be 1/10 to 1/20 of the open loop gain at a given frequency to ensure that the op-amp will operate without distortion.

23. Open and Closed Loop Response

24. Important Parameters for Op-Amps
Input Parameters
Voltage (Vicm)
Offset voltage
Bias current
Input Impedance
Output Parameters
Short circuit current
Voltage Swing
Open Loop Gain
Slew Rate

25. Where to buy Op-Amps
Newark Electronics
Radio Shack
DigiKey
Jameco

26. References
David G Alciatore & Michael B. Histand, Introduction to Mechatronics and Measurement Systems
Electronics book

27. Questions ?