Amplifiers Flashcards
Used to increase the amplitude of a signal waveform, without changing other parameters of the waveform
Amplifier
What are the parameters of the waveform that is not changed by the amplifier?
Frequency or wave shape
Small Signal -> Common Emitter -> ? -> ?
Class A Amplifier; Direct Current (DC)
Large Signal -> Common Base -> ? -> ?
Class B Amplifier; Audio Frequencies (AF)
Common Collector -> ? -> ?
Class AB Amplifier; Radio Frequencies (RF)
Class C Amplifier -> ?
VHF, UHF, and SHF Frequencies
Linear devices that have all the properties required for nearly ideal DC amplication
Operational Amplifiers (op amps)
Op amps is used extensive in s_ c_ f_ or to p_ m_ o_
signal conditioning; filtering; perfom mathematical operations
What are the mathematical operations that op amps can do?
Add, Subtract, Integration, Differentiation
In Op Amps, V1 represents?
Hint: I_ I_ or I_ A_
Inverting Input
Inverting Amplifier
In Op Amps, V2 represents?
Hint: N_-I_ I_ or N_-I_ A_
Non-inverting input
Non-inverting Amplifier
DVPS
Dual Voltage Power Supply
Very _ input impedance but very _ impedance on the output voltage
high; low
Vout =
Aol(V2-V1)
Aol refers to
Open loop gain
Importance of Op Amps to Analog Electonics
They make use of n_ f_ easy and straightforward and confer on any circuit where they are used.
Negative feedback
Importance of Op Amps to Analog Electonics
Op amps are still a p_ b_ b_ for analog systems, performing tasks like a_, a_ f_, and s_ t_.
primary building block; amplification; active filtering; signal transformation
The return of a portion of the output signal to the input signal (out-of-phase)
Negative feedback
If op amp has feedback, its operation is
Closed loop
If op amp is with no feedback, the operation is
Open loop
Formula for Output Voltage in Op Amps
Vo = Av (V+ - V-)
Op amps have two inputs, what is it?
Noninverting and inverting input
Input whose voltage is designated V+
Noninverting input
Input designated V-
Inverting
Most op amps have a s_ o_ lead, which carries the output voltage V_
Single output, Vo
Most op amp require d_ DC power supplies, designated _ and _
Dual; +Vs; -Vs
The ideal op amp’s input terminal draw no c_ from the source voltages connected to them. This means that the ideal op amp has i_ i_ i_
current; infinite input impedance
4 basic building blocks of an op amp
B, 2, G, B
Bias Section
2:1 Section
Gain Section
Buffer Stage
Under bias section:
Provide constant voltage into small circuits but it must be maintained.
Bandgaps
Under bias section:
Provide constant current into small circuits but it must be maintained.
Current mirrors
Under 2:1 Section:
There are _ inputs and _ output on an op amp
Two; one
Under 2:1 Section:
This stage is somewhere on the i_
Inside
Under 2:1 Section:
Two transistors hooked to a common current source
Differential Pair
Under Gain Section:
= I_ section
= _ is bigger than the _
= Smallest difference in the _ voltages can cause issues on _
Important
Output; Input
Input; Output
Under buffer stage:
= protects _ circuit
= drives the _
= _ voltage and the _ voltage are equal
= provides more _ which makes into more _
Gain
Load
Input; Output
Current; Power
Assume that input terminals have infinite impedance and draw no current. The summing junction have V =0
HINT:
IA and NA
Inverting Amplifier
Non-inverting Amplifier
Vary the resistances to set the negative gain
Inverting Amplifier
Vary the resistances to set the positive gain
Non inverting Amplifier
X
Virtual Earth Summing Point
Assume that input terminals have infinite impedance and draw no current. Use superposition to calculate Vout from V1, V2, and V3. Then sum the output voltages to find total output
Summing Amplifier
Applies external voltage to both inputs, making it useful for amplifying sensor signals. The principle of superposition is used again here.
Differential Amplifier
The output of the differential amplifier is d_ p_ to the difference of the two external V1 and V2, where gain is given by R3 divided by R1
Directly propotional
A form of differential amplifier where the inputs are buffered by two op amps
Instrumentation Amplifier
Increases the disparity among two inputs
One kind of IC or integrated circuit
Instrumentation Amplifier
Instrumentation Amplifier is designed specifically for sensor inputs with its
* variable h_ g_
* high i_ i_
* low i_ o_ d_
* high c_ m_ r_
High gain
Input impedance
Input offset drift
Common mode rejection
Used to amplify small differential signals for thermocouples, strain gauges, current sensors used in motor controls
Instrumentation Amplifier
The _ are specifically set up for amplifying sensor signals
Pinouts
The op-amps 1&2 are n_ and op-amps 3 is a d_ a_. These what form an instrumentation amplifier
Non-inverting; difference amplifier
Advantages of Instrumentation Amplifier:
The gain of a three op-amp instrumentation amplifier circuit can be easily varied by adjusting the value of only _ resistor: _
One; Rgain
Advantages of Instrumentation Amplifier:
The gain of the amplifier depends only on the e_ r_ used
External resistors
Advantages of Instrumentation Amplifier:
The i_ i_ is very h_ due to the e_ follower configurations of amplifiers 1 and 2
Input impedance; high; emitter
Advantages of Instrumentation Amplifier:
The o_ i_ of the instrumentation amplifier is very l_ due to the difference amplifier 3
Output impedance: low
Advantages of Instrumentation Amplifier:
The _ of the op-amp 3 is very high and almost all of the common mode signal will be rejected.
CMRR
Applications of Instrumentation Amplifier:
These amplifiers mainly involve where the accuracy of h_ d_ g_ is required, s_ must be preserved in n_ surroundings, as well as where huge c_-m_ signals are there
High differential gain
Strength; noisy surroundings
Common-mode
Applications of Instrumentation Amplifier:
Instrumentation amplifiers are used in d_ a_ from small o/p t_
Data acquisition; transducers
Small o/p transducers are:
hint: t, s g, m of w b
Thermocouples
Strain gauges
Measurements of Wheatstone bridge
Applications of Instrumentation Amplifier:
These amplifiers are used in n, m, r etc
Navigation, medical, radar
Applications of Instrumentation Amplifier:
These amplifiers are used to enhance the / ratio in audio applications like audio signals with low amplitude
S/N (signal to noise)
Applications of Instrumentation Amplifier:
These amplifiers are used for i_ as well as v_ d_ a_ in the conditioning of high-speed signal
Imaging
Video data acquisition
Applications of Instrumentation Amplifier:
These amplifiers are used in _ cable systems for amplication of the high-frequency signal
Radio Frequencies (RF)
Difference Between Op Amp and Instrumentation Amp:
A/n _ is one-kind of an IC
Operational Amplifier
IC means
Integrated circuit
Difference Between Op Amp and Instrumentation Amp:
The _ amplifier is one type of differential amplifier
Instrumentation
Difference Between Op Amp and Instrumentation Amp:
_ amplifier can be built with three operational amplifier
Instrumentation
Difference Between Op Amp and Instrumentation Amp:
The _ amplifier can be built with a single operational amplifier
Differential
Difference Between Op Amp and Instrumentation Amp:
The o_ v_ of difference amplifier gets affected because of the m_ r_
Output voltage; mismatch resistors
Difference Between Op Amp and Instrumentation Amp:
_ amplifier offers gains with a single resistor of its primary phase which does not need a resistor matching
Instrumentation
