The logic gates are the basic building blocks of the binary logic circuits which are used in digital system.
A logic simply an electronic circuit that operates an one or more input signal to produce an output signal.
Commonly used gates in digital system
The output of AND gate is high only when all the input are heigh.When any one of the input is low the output is low.
The output of OR gate is high when any of the input is high and the output is low only when all the inputs are low.
The output of NOT gate is the complement of the input.
NAND gate is functionally equivalent to an AND gate followed by a NOT gate. Hence the output of the NAND gate is the compliment of the output of AND gate.
The output of the NOR gate is the compliment of the output of OR gate.
The output of the exclusive OR gate is high only if one and only one of the input is high and hence the name exclusive OR.
The first theorem is states
The compliment of the product of two variables is equal to the sum of the compliment of each variable
If A and B are the two inputs
(A.B)’ = A’ + B’
Where ‘complement
The second theorem is states.
The compliment of the sum of two variables is equal to the product of the compliment of each variable.
If A and B are the two inputs
(A+B)’ = A’ . B’
Where ‘ complement
In the binary number system there are only two digits ‘0’ and ‘1’.Binary number conversion.
For binary number conversion refer Binary Decimal Octal and Hexadecimal number systems(Analog and Digital Electronics)
Thyristor is used for switching device ,Its construction and operation of the silicon controlled rectifier.Thae main parts of thyristor are anode,cathode and gate.Thyristor turn ON need small trigger pulse of current in to the gate terminal when the thyristor is in its forward direction.
Thyristor are semiconductor device and they are specially designed for the for use in highpower switching applications
A combinational circuit can be defined from the behavioral point of view as a circuit whose output is dependent only on the inputs at the same time instant.
The behavioral point of view as a circuit whose output depends not only on the present inputs but also on the past history of inputs.
Flipflop, Counters, Registers and accumulator
Operational amplifier abbreviated as OPAMP ,was originally the name of circuit used for carrying out mathematical operation such as addition , subtraction , multiplication, division, integration, differentiation etc of electrical signal.
An opamp is a high gain direct coupled voltage amplifier to which feed back is added to control the overall response characteristics.
Typically an OPAMP has two input terminal and one output terminal and gain of at least 10^5.In the symbol the input terminal with ‘‘ mark is the inverting input terminal, with’+’ mark is non inverting input terminal.
CMRR
Is the ratio of the differential mode gain to the common mode gain of OPAMP.
CMRR=Adm/Acm
An ideal OPAMP is one which has the following characteristics

a. Differential voltage gain = infinity
b. Common mode voltage gain =0
c. Band width = infinity
d. Input resistance= infinity
e. Output resistance= 0
f. CMRR =infinity
g. Output voltage =0,when input voltage =0
h. Parameter drift with temperature =0
i. Equivalent input noise= 0
Oscillator is an electronic device that produces an output wave form without any external signal. The only input to an oscillator is the dc power supply.
Oscillator can defined as a converter of dc energy in to ac energy.
This device used for producing sine waves such as square wave, saw tooth wave, rectangular wave etc. Multi vibrators are basically two stage amplifier.
IC (Integrated circuit are available for the regulated power supply.)
The low frequency intelligence is transmitted with the help of a high frequency carrier wave .The process of making this carrier convey the low frequency signal is called modulation.
Three types of modulation
Amplitude modulation, Frequency modulation, Phase modulation.
Radio broadcasting, Trans receiver communication, microwave communication , submarine ,ship.
Frequency modulation
Sound transmission TV, Stereosound transmission, satellite communication, mobile services.
For sine wave input output will be a cosine wave.
Clipping and clamping
The circuit which is used to change the shape of an input signal by removing a portion of it without destroying the remaining part of the wave is called clipper.
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