Dtl diode transistor logic nand gate o nand gate is a electronic circuit which has two or more inputs but only one output. Printexport export pdf export png export eps export svg export svgz description a xor gate using nand gates. From the truth table, we can say that the output of the or logic or an or gate is true or high or 1, even if either or both of a or b are 1. The inputs to the nand gate is applied through the diodes and these diodes are connected to bjt. Logic gates application, logic gate pdf, logic gates pdf notes, universal logic gate, online study point logic gates are the basic building blocks of any digital system.
So, from the above discussion, it is clear that all the three basic gates and, or, not can be made by only using nor gate. This diagram shows how to make a simple dtl circuit that has the same function as a nor gate. The nor gate is a digital logic gate that implements logical nor it behaves according to the truth table to the right. In case of nand gate, 3 pmos will be connected in parallel and 3 nmos will be connected in series, and other way around in case of 3 input nor gate. The equivalent circuit of nand gate using diodes and transistors is shown below. Lets see why these are preferred and how we can design other gates by using nand gate. The nand based derivation of the or gate is shown in figure 1. Analysis of cmos based nand and nor gates at 45 nm technology. Several kinds of digital logic circuits are the basic elements that form the building blocks for such complex digital system as the. Logic nor gate tutorial the logic nor gate gate is a combination of the digital logic or gate and an inverter or not gate connected together in series the inclusive nor notor gate has an output that is normally at logic level 1 and only goes low to logic level 0 when any of its inputs are at logic level 1. Finally, from the results, we can conclude that the derived configuration of the nand gates is correct and indeed is equivalent to an.
The circuit diagram is similar to that of not gate made by using only nand gate. In most of the cases, binary low is represented using the zero volts 0 v. The logic gate nor takes two or more input and works as per the following truth table. A basic cmos structure of any 2input logic gate can be drawn as follows. Logic nand gates are available using digital circuits to produce the desired logical function and is given a symbol whose shape is that of a standard and gate with a circle, sometimes called an inversion bubble at its output to represent the not gate symbol with the logical operation of the nand gate given as. That using a single gate type, in this case nand, will reduce. O the nand gate is the natural implementation for the simplest and fastest electronic circuits o the output is high if at least one of its input is low. Logic gates and truth table and, or, not, nor, nand, xor. How a nand gate can be used to replace an and gate, an or gate, or an inverter gate. B b parallel switches b series form or a switches form a. Design of basic logic gates using nor gate not, or and and. Logic gates not, or, and, nor, nand, xor, xnor gate, pdf. Nand gate, nor gate which are extensively used in the designing of the more complex circuits with higher. Implementing logic functions using only nand or nor gates.
A cd4011b was used as an example of a nand gate ic. Today, contrary to popular belief, integrated circuits are not constructed exclusively from a single type of gate. Today we have learned about complete details on logic gates not, or, and, nor, nand, xor, x nor gate, pdf. Click on the inputs on the bottom to toggle their state. We can create and, or and not gate using the nor gate.
When both input a and b are given with 0 v, both of the diodes are in forward biased condition that is in on condition. For the breadboard part of this step, the blue wire represents input 1 a, wire 2 represents input 2 b, and the led represents the final output. How a logic circuit implemented with aoi logic gates can be reimplemented using only nand gates. Basic logic gates and, or, and not gates objectives. Diode and transistor nand gate or dtl nand gate and nand gate.
Logic nor gate tutorial with logic nor gate truth table. Aug 04, 2015 in case of nand gate, 3 pmos will be connected in parallel and 3 nmos will be connected in series, and other way around in case of 3 input nor gate. The output gate must be a or gate andgate outputs cannot be used as andgate. The boolean expression for a logic nand gate is denoted by a single dot or full stop symbol. The above drawn circuit is a 2input cmos nand gate. Logic design unit 7 multilevel gate circuits sauhsuan wu two of the most commonly used circuits are the nand nand and the nor nor procedure for designing a min 2level nand nand circuit find a minimum sop for f draw the corresponding twolevel andor circuit replacing all gates with nand gates.
Hence a nor gate is made up from a or gate which is followed by an inverter. This is an nor gate implemented using transistortransistor logic. A digital computer performs complicated operations by interconnecting a large number of switches called logic gates. The design is very similar to the transistor gates shown in this multipart article. Apr 04, 2018 step by step procedure to implement nand gate by using only nor gates. Universal logic gate nor logic gate dyclassroom have.
Pdf analysis of cmos based nand and nor gates at 45 nm. When the inputs of both diodes of nand gate are connected to a high voltage level i. A high output 1 results if both the inputs to the gate are low 0. Logic gates application, logic gate pdf online computer. Lets take a look at the symbol and truth table for or gate first. We have seen how nand gate can be used to make all the three basic gates by using that alone. The gate is either a nand or an ex or gate b nor or an exnor gate c an or or an ex nor gate d an and or an exor gate gate 1994. Sometimes when youre building circuits, you dont always have the right components. Universal gates in digital electonics nand and nor. And thus, it can be aptly termed as universal gate. Analysis of cmos based nand and nor gates at 45 nm. Now lets understand how this circuit will behave like a nand gate.
Logic gates application, logic gate pdf online computer study. It produces a 1 output when any of the inputs is 0. It is an electronic circuit having one or more than one input and only one output. Digital circuitsnor logic wikibooks, open books for an. Fortunately when it comes to digital logic gates, you can make the component you need. Similarly, we can implement any boolean function, which is in product of sums form by using nor gates alone. For simplicity we will show here only two inputs nand gate circuit by using diodes and transistors. To build an or gate from a nand gate, we need to use 3 of the 4 gates that a 4011 nand chip offers. Logic gates application, logic gate pdf, logic gates pdf notes, universal logic gate, online study point. Cmos technology and logic gates mit opencourseware. Because we can implement any boolean function, which is in sum of products form by using nand gates alone.
Like nand gates, nor gates are socalled universal gates that can be combined to form any other kind of logic gate. Nand gate is a digital circuit that has two or more inputs and produces an output. Mostly, we prefer nand gates over nor gates for designing the other basic logic gates. The different interconnections are designed to implement the laws of logic. Diode and transistor nand gate or dtl nand gate and nand. With regard to the previous point, an and gate is really formed from a nand gate followed by a not gate similarly, an or gate consists of a nor gate followed by a not gate. In product of sum form, 1st level of the gate is or gate and 2nd level of the gate is and gate.
The output of a logic gate is 1 when all its input are at logic 0. Implement nand gate using nor gates only logic gates. Nov 12, 2016 this video takes the viewers, step by step to four different derived gates, i. This is a transistortransistor logic ttl nand gate circuit using bipolar junction transistors. It produces a 0 output only when all the inputs are 1.
Conceptually, the or gate is built from nand gates through the following diagram. Department of communication engineering, nctu 23 logic design unit 7 multilevel gate circuits sauhsuan wu the following procedure may be used to design multi level nandgate circuits simplify the switching function to be realized design a multilevel circuit of and and or gates. A basic circuit using any generalpurpose bipolar transistor such as the bc549, bc548, or bc547, could be used to construct the gate. Each output and output of a logic gate is represented by binary conditions 0 low and 1 high. That is, given enough gates, either type of gate is able to mimic the operation of any other gate type. Watch this video to learn more and see the interesting practical. Sep 07, 2015 the word nor gate is just an short form of the not and or gate combination. Gate universality logic gates electronics textbook. The above diagram is of a not gate made by using a nor gate.
If youre fresh out of nor gates, but have some nand gates laying around, youre in luck. Now let us see how each logic gate can be created with nand and nor 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. In fact, most gates are implemented in solidstate ttl chips transistortransistor logic. The importance of nand nand gates are considered to be the universal gate, because any other gate can be synthesized eve engels, 2006 slide 22 of 20 using nand. How to draw a nand gate using only nor gates quora. The implementation of a fulladder using two halfadders and one nand gate requires fewer gates than the twolevel network. The circuit output should follow the same pattern as in the truth table for different input combinations.
The ability for a single gate type to be able to mimic any. It can also in some senses be seen as the inverse of an and gate. That using a single gate type, in this case nand, will reduce the number of integrated circuits ic required. May 24, 2014 logic gates and, or, not, nor, nand, xor, xnor gates. The logic or boolean expression given for a logic nand gate is that for logical addition, which is the opposite to the and gate, and which it performs on the complements of the inputs. The implementation is on a solderless breadboard using discrete components. Very quickly, below are the symbols, boolean expression and truth table of nand and nor gates. This is because, this gate can function as any of the basic logic gates by just making some changes at its input side.
Conceptually, the and gate is built from nand gates through the following diagram. A universal gate is a gate which can implement any boolean function without need to use any other gate type. An or gate equivalent can also be constructed using only nand gates, by putting two shorted equivalent to not nand gates each at the input of a third nand gate as shown in figure 4. See the newest logic products from ti, download logic ic datasheets, application notes, order free samples, and use the quick search tool to easily find the best logic solution. Use of the two symbols facilitates analysis and synthesis using these gates. Digital logic nand gate universal gate electrical technology. Jul 08, 2015 nand gates are called universal gates. Universal gate nand i will demonstrate the basic function of the nand gate. As a nor gate is equivalent to an or gate leading to not gate, this automatically sees to the or part of the nor gate, eliminating it from consideration and leaving only the not part. Apologies for the quality of images using nand gate. For example, the, apollo guidance computer, was built exclusively from nor gates, about 5,600 in total for the later versions. This is a very simple nor gate circuit construction using a pair of diodes and a transistor. This video takes the viewers, step by step to four different derived gates, i.
Logic nand gate tutorial with nand gate truth table. In this circuit, we have two bipolar transistors connected in series across the light emitting diode led. An or gate equivalent can also be constructed using only nand gates, by putting two shorted equivalent to not nand gates each at the input of a third nand gate as. Implementing twolevel logic using nor gate requires the boolean expression to be in product of sum pos form. Nor is the result of the negation of the or operator. So we can see that all the three basic gates can be made by only using nand gates, thats why this gate is called universal gate and it is appropriate. Logic gate actually the term logic is applied to digital circuits used to implement logic functions. Logic gates and, or, not, nor, nand, xor, xnor gates. To build an and gate from a nand gate, we simply need to use 2 of the 4 gates that a 4011 nand chip offers. The word nor gate is just an short form of the not and or gate combination. Step by step procedure to implement nand gate by using only nor gates.
For example, it is possible to build a circuit exhibiting the or function using three interconnected nand gates. The same pattern will continue even if for more than 3 inputs. When it comes to digital logic gates, you can make the component you need. The nandbased derivation of the or gate is shown in figure 1. This nand gate is called dtl nand gate or diode transistor logical nand gate. Logic gates and truth table and, or, not, nor, nand, xor, xnor. Design of basic logic gates using nor gate not, or and. Nand gate, nor gate which are extensively used in the designing of.
To implement a boolean function using nor gate, there are basically three step. The above diagram is of an and gate made from nand gate. Jan 04, 2020 the above diagram is of a not gate made by using a nor gate. The logic diagram of any boolean function can be drawn using a twolevel nand gates or twolevel nor gates.
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