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Author of this note Mr. K. Prasad BSc from University of Calicut, MSc from university of Delhi, and M.B.A from IGNOU Delhi, These notes were prepared during my teaching session for under graduate students (11th and 12th class) of my school Physics department. This note is helpful for under graduate students and junior level graduates. I declare that these notes are my original works based on my knowledge in physics and the books mentioned below are the reference books I used for preparing these notes TABLE OF CONTENTS (1) Difference between Analog and Digital Circuits, (2) Working of Analog Circuit and Digital Circuits, (3) O/P Quality, (4) Efficiency of a Circuit, (5) Precision and Reproduction capacity,
**(6) Differences between analog circuit and digital circuits, (7) Advantages of Digital Circuits, (8) Disadvantages of Digital Circuits, (9) Examples of linear and digital ICs (10)Binary numbers in digital electronics, (11)Octal and hexadecimal numbers, (12)Why do we use octal and hexadecimal number system? (13)How is octal number calculated? (14) How can we implement AND gate using diode? (15)NAND, AND NOR gates as universal gates, (16)XOR and XNOR gates and application as parity checker, Reference Books:
- Digital Principles and Applications, A.P.Malvino, D.P.Leach and Saha, 7 th**^ **Ed., 2011, Tata McGraw
- Fundamentals of Digital Circuits, Anand Kumar, 2 nd**^ **Edn, 2009, PHI Learning Pvt. Ltd
- Digital Circuits and systems, Venugopal, 2011, Tata McGraw Hill
- Digital Electronics G K Kharate 2010, Oxford University Press
- Logic circuit design, Shimon P. Vingron, 2012, Springer.
- Digital Electronics, Subrata Ghoshal, 2012, Cengage Learning
- Digital Electronics, S.K. Mandal, 2010, 1st**^ **edition, McGraw Hill
- Microprocessor Architecture Programming & applications with 8085, 2002, R.S. Goankar, Prentice Hall**
waves. These signals can be put away on the strip, worked on in an analog amplifier and changed back to related sound waves by a speaker. A digital circuit is utilized to modify the waves into pulse waves. It estimates a waveform thousands of times consistently and stores the information in binary form. For example, after 12msecs, a sign may be 2.4 volts high and after 14msecs, it very well may be at 2.6 volts. This circuit changes the volts and times into binary data, and the waves become a progression of 1's and 0's. Whenever the circuit needs to create sound from a speaker, it delivers an o/p signal which is at 2.4 V after 12msec and at 2.6 V after 14msec, like the first wave. O/P Quality Analog circuit conveys an analog of the common wave structure and can create exceptionally high o/p quality. Digital circuits create a gauge of the normal waveform, so their nature of o/p is fragmented by the quantity of curve size they complete. Efficiency of a Circuit, An efficiency of a circuit primarily relies on how quickly it can deliver results and how much power it uses. These circuits need to trust that a wave will go full circle before they can complete their tasks. What's more, they require adequate ability to create the pinnacle of the wave. The digital circuit's speed is fragmented exclusively by the speed of the gears that make up the circuit and not by the signals they are handling. To work with small pulses needs respectably little power. In the majority of the applications, analog circuits are slower and require more power than digital circuits. Precision and Reproduction capacity, The demonstration of simple circuits relies upon their plan and their gears to ensure the waveform extras consistent with the first. They are at risk to configuration faults, adjusts from maturing parts and outside powers like electrical noise. Digital circuits simply need to keep up with way of their pulses. Regardless of whether various pulses get vanished, it impacts a couple of the
great many sizes. Therefore, these circuits are more exact and can repeat their I/ps all the more precisely. Differences between analog circuit and digital circuits, In digital circuits, the i/p signals change from analog to digital (A/D) form before it is processed, that is the digital circuit is accomplished by processing digital signals only, and generates o/p which is again changed back from digital to analog signals (D/A) so that the o/p gives relevant results that can be understood by individuals. Analog circuits are typically routine made and they don’t have flexibility Digital circuits have a high degree of elasticity. Digital circuits are very simple to design since the technique of an automation can be useful at a variety of levels of circuit design. No change of i/p signals is necessary before processing; the circuit straightly executes different logical operations and generates an analog o/p. Analog circuits operate on analog signals commonly known as continuous valued signals Digital circuits function on signals that exist simply at 2 levels, i.e. Zeros and ones The designing of an analog circuit is difficult since every component has to be positioned by hand for designing the circuits. Advantages of Digital Circuits A digital circuit can be utilized to reduce the noise and produce right signals. As digital circuits are comprised of essential rationale gates, they are not expensive Digital circuits can be utilized for exact representation of the circuit Exchanging time is a lot quicker when contrasted with of analog circuits. Disadvantages of Digital Circuits,
How is octal number calculated? In case of decimal to octal, we divide the number by 8 and write the remainders in the reverse order to get the equivalent octal number. Decimal Number: All the numbers to the base ten are called decimal numbers. These are the commonly used numbers, which are 0-9. How can we implement AND gate using diode? Image result for AND, OR and NOT Gates (realization using Diodes and Transistor) AND Gate using diodes Circuit on Breadboard Place the two diodes as shown in figure below Connect two jumper wires at the N-terminal of each diode. Connect the P terminal of each diode together. Connect the resistor from p terminal of Diodes to V (battery's +ve terminal)
While diode logic has the advantage of simplicity, the lack of an amplifying stage in each gate limits its application. Not all logical functions can be implemented in diode logic alone; only the non-inverting logical AND and logical OR functions can be realized by diode gates. Diode logic gates use diodes to perform OR and AND logic functions as shown in the circuit diagram. Connection of the LED at the output is optional which simply displays the logical state of the output, i.e. the logic state of output is 0 or 1, if LED is off or on, respectively. The NOT gate is the basic logic gate among all the gates. It gives only one output which is the negation value of the corresponding input. When the input is forced to low value it gives high value at the output and vice – versa. A transistor is used for switching or amplification purpose. NAND, AND NOR gates as universal gates, The OR, AND, and NOT are the three basic logic gates as they together can construct the logic circuit for any given Boolean expression. NOR and NAND gates have the property that they individually can be used to hardware-implement any logic circuit. For this reason, the NAND and NOR gates are called universal gates. The NOR gate and NAND gate are universal gates. This means that you can create any logical Boolean expression using only NOR gates or only NAND gates, In practice, this is advantageous since NOR and NAND gates are economical and easier to fabricate than other logic gates. A universal gate is a gate that can implement any Boolean function without using any other gate type. For example, the NAND and NOR gates are universal gates. In practice, this is advantageous since NAND and NOR gates are economical and easier to fabricate and are the basic gates used in all IC digital logic families. XOR and XNOR gates and application as parity checker, XOR gate design: A parity checker is designed by using XOR gates on the bits of the data. An XOR gate will output a "0" if bits are similar or a "1" if the bits differ.
