2. introduction
Introduction
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
4. introduction
Operational Amplifiers
Five important pins
2 – The inverting input
3 – The non-inverting input
6 – The output
4 – The negative power supply V-
(-Vcc)
7 – The positive power supply V+
(+Vcc)
5. introduction
Operational Amplifiers
The output of the op amp is given by the following
equation:
Vd = E1 – E2
and Vo = AVOL(Vd)
AVOL is called the open-loop voltage gain because it
is the gain of the op amp without any external feedback
from output to input
13. introduction
Operational Amplifiers
An ideal op-amp has infinite gain and bandwidth,
we know this is impossible.
However, op-amps do have:
very high gain
very high input impedance(Zin = ∞)
very low output impedance (Zout = 0)
wide bandwidth.
14. application
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
15. application
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+
> V-
VO = -VEE if V+
< V-
Input current, Ii = 0
Application in op-amp
18. application:inverting amplifier
Application: Inverting amplifier
Provide a constant gain multiplier
Input signal is connected to the inverting input of the op-
amp. 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
21. 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
26. Summing Amplifier
V1
V2
V3
R1
R2
R3
Rf
This circuit is called
a weighted summer
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36. non-linear application
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+
> V-
VO = -VCC if V+
< V-
Input current, Ii = 0
Recall: Non-linear application in op-amp