OP AMP Applications

Electronics Circuit Design Presentation on OP AMP APllications

1. ECD II Presentation OP-AMP Applications

2. Presented by Group 12 Aroosa Sheher Sidra Ali

3. Introduction What is OP-AMP Mathematics of OP-AMP Characteristics of OP-AMP Ideal OP-AMP Types of OP-AMP Applications of OP-AMP Description of OP-AMP applications

4. What is Op Amp An Operational Amplifier (Op-Amp) is an integrated circuit that uses external voltage to amplify the input through a very high gain What an Op-Amp looks like to a lay-person

5. What is an Op-Amp? – The Surface . What an Op-Amp looks like to an engineer

6. What is an Op-Amp? – The Inside The actual count varies, but an Op-Amp contains several Transistors, Resistors, and a few Capacitors and Diodes. For simplicity, an Op-Amp is often depicted as this: Inverting Input Non-Inverting Input Positive Power Supply Negative Power Supply Output

7. Mathematics of the Op-Amp The gain of the Op-Amp itself is calculated as: G = V out /(V + – V - ) The maximum output is the power supply voltage When used in a circuit, the gain of the circuit (as opposed to the op-amp component) is: A v = V out /V in

8. Op-Amp Characteristics Open-loop gain G is typically over 9000 But closed-loop gain is much smaller R in is very large (M Ω or larger) R out is small (75 Ω or smaller)

9. Ideal Op-Amp Characteristics

10. Types of Op-Amps  I nverting N on-inverting S umming   amplifier T he  voltage follower  I ntegrator Differentiator

11. Applications of Op-Amps Comparator Integration and differentiation Charge amplifier Capacitance multiplier Oscillators Filters A udio and video preamplifiers and  buffers

12. Applications of Op-Amps Voltage regulator and current regulator Digital-to-analog converter Voltage clamps Oscillators and  waveform generators Analog computer

13. Comparator C ompares two voltages or currents and outputs a digital signal indicating which is larger. T wo analog input terminals and one Output . The op-amp's output voltage is limited by the supply voltage.

14. Integration P erforms the mathematical operation of Integration . O utput signal is determined by the length of time a voltage is present at its input as the current through the feedback loop charges or discharges the capacitor as the required negative feedback occurs through the capacitor.

15. Differentiation A mplifies the difference between two voltages but does not amplify the particular voltages. =Common-mode gain of the amplifier . = Differential gain U sed to null out noise or bias-voltages that appear at both inputs, a low common-mode gain is usually desired.

16. Differential and C ommon Gain   Differential Gain  (A d ): A d  = 1/2[R 3 /(R 1 +R 3 )] [(R 4  + R 2 )/R 2  + R 4 /R 2 ] Mode Gain  ( A cm =V OUT / V cm ) A cm  = [R 3 /(R 1 +R 3 )] [(R 4  + R 2 )/R 2  - R 4 /R 2 ] 

17. Charge amplifier C onstructed using op-amps with a feedback capacitor . The charge amplifier just transfers the input charge to another reference capacitor and produces an output voltage equal to the voltage across the reference capacitor T he circuit acts as a charge-to-voltage converter . The input impedance of the circuit is almost zero  

18. Capacitance Multiplier U ses an amplifier to make a capacitor function like a capacitor that is much large . U sed as a capacitance multiplier in such a way that multiple small physical capacitances are combined in the integrated circuit technology to yield a large overall capacitance. The aim is often to multiply the original capacitance value hundreds and thousands of times.

19. O scillators P roduces a repetitive, oscillating electronic signal, often a sine wave or a square wave. convert direct current (DC ) from a power supply to an alternating current signal. It contains an energy-storing element (a capacitor or , more rarely, an inductor )

20. Active FILTERS Types : Low pass filter High pass filter Band pass filter Band reject filter

21. Active Filters A filter contains a device like an Op Amp LP allow low frequencies HP allow high frequencies Cut of frequency : a cutoff frequency is a frequency level above or below where a device fails to operate. R 2 + - + V __ + V cc - V cc - + R 1 C Low pass filter Low pass filter transfer function  Low pass filter Cutoff frequency 

22. Low Pass Filter Passes low frequency signals with amplification and gain control

23. Active Low Pass Filter with Amplification the amplitude of the output is increased by the pass band gain, A F of the amplifier.

24. Frequency Response Curve

25. High Pass Filter P asses high frequency signals with amplification and gain control First Order Active High Pass Filter with 1 Gain  

26. Active Band P ass Filter   F requency selective filter circuit  R ange is set between two cut-off frequency points “ lower frequency” (  ƒ L  ) and the “higher frequency” (  ƒ H  ) while attenuating any signals outside of these two points. M ade by cascading together a single  Low Pass Filter with a single  High Pass Filter   .

27. Active Band Pass Filter Circuit

28. Band reject filter Band stop filters reject a specified band of frequencies and pass all others. The response is opposite to that of a bandpass

29. Graphical representation

30. That’s all THANKS