Here we will use the very versatile IC 4093 which is comprised of 4 NAND gates (Schmitt Trigger) and see how we can wire them up into a few amazing, yet simple circuits. ¯ The truth table of an OR gate is also given beside the diagram. Full adder is a simple 1 – bit adder. The following circuit according to the correct or incorrect operation of the NAND gate manufactures output. What is a Schmitt Trigger. Since the logic circuit involves an AND gate followed by an inverter. A NAND gate (“not AND gate”) is a logic gate that produces a low output (0) only if all its inputs are true, and high output (1) otherwise. It shares this property with the NOR gate. The circuit of full adder using only NAND gates is shown below. Each of this gates can realize the logic circuits single handedly. The boolean expression is now standardized such that it can completely be represented by a NAND gate at every input level. https://en.wikipedia.org/w/index.php?title=NAND_gate&oldid=996422683, Srpskohrvatski / ÑÑÐ¿ÑÐºÐ¾Ñ
ÑÐ²Ð°ÑÑÐºÐ¸, Creative Commons Attribution-ShareAlike License, This page was last edited on 26 December 2020, at 14:38. By connecting the NAND gates together in various combinations the three basic gate types of AND , OR and NOT function can be formed . Fire Alarm Circuit; Digital UP/DOWN Counter The circuit schematic for an AND gate from a 4011 NAND gate chip is shown below. That is, any other logic function (AND, OR, etc.) So with two buttons we can realize the truth table of NAND gate. Let’s take a look at the symbol and the truth table. A digital mux is a two input digital component that lets you select one of the two inputs based on the state of a third digital input. One way of expressing A NAND B is A NAND gate is made using transistors and junction diodes. Fire Alarm Circuit; Digital UP/DOWN Counter; Different types of oscillator circuit; Switching Circuit; An automatic watering system with timer; making a xor gate using nand gate; Nand gate can implement any Boolean Function; Nand Gate can b used as inverter,battery monitor circuits . Each of them performs a different logic function. What is a NAND Gate? This means that if either of these things happen, i.e. The logic symbol for the gate is shown below: The logic circuit of the NAND gate is shown below: From the logic circuit, the output can be expressed as: The equation is read as âZ equals NOT A AND Bâ. Now that you know how a NAND gate works, let’s design a simple circuit where a NAND gate performs a real-life task. It has 2 inputs X, Y and single output, Z. A LOW (0) output results only if all the inputs to the gate are HIGH (1); if any input is LOW (0), a HIGH (1) output results. Logic gates are commonly used in integrated circuits . You likely find the 4011 IC marked as CD4011, NTE4011, MC14011, … How to change a combinational logic circuit from AND, NOT, and OR gates to only NAND gates or only NOR gates. This property is called functional completeness. AOI (AND/OR/INVERT(NOT)) can be converted to NAND logic or NOR logic. the switch is closed or the light is on one of the inputs is LOW, the output is HIGH and the buzzer sounds. An OR gate is a logic circuit in which one HIGH value at any of the inputs will turn the output HIGH (on). The circuit shown below is a basic NAND latch. A NAND gate circuit is almost identical to an AND gate circuit. The NAND gate provides the false or low output only when their outputs is high or true. Datasheets are readily available in most datasheet databases. Application of Nand Gate. How to change a combinational logic circuit from AND, NOT, and OR gates to only NAND gates or only NOR gates. The NAND-based derivation of the NOT gate is shown in Figure 1. NAND gates can also be used to produce any other type of logic gate function, and in practice the NAND gate forms the basis of most practical logic circuits. The expression for the NAND gate is ‘—‘whole bar. In the NOR gate version we had to use a separate 74LS08 integrated circuit. ¬ B. an AND gate. The standard 2-, 3-, 4- and 8-input NAND gates are available: The NAND gate has the property of functional completeness, which it shares with the NOR gate. Inexpensive and easy to use. B Hence the NAND gate is the inverse of an AND gate, and its circuit is produced by connecting an AND gate to a NOT gate. Oscillator: You will need just a resistor and a capacitor to build an oscillator from these gates. The function completeness means any types of gates can be implemented by using the NAND gate. Square Wave Generator Circuit Diagram. When the switch is closed one input of the NAND gate is LOW. We can obtain NAND logic by just connecting a NOT gate to an AND gate. {\displaystyle {\overline {A\land B}}} A NAND gate (sometimes referred to by its extended name, Negated AND gate) is a digital logic gate with two or more inputs and one output with behavior that is the opposite of an AND gate.The output of a NAND gate is true when one or more, but not all, of its inputs are false.If all of a NAND gate's inputs are true, then the output of the NAND gate is false. A NAND gate is a digital circuit that has two or more inputs and produces an output, which is the inversion of logical AND of all those inputs. The following table shows the truth table of 2-input NAND gate… The NAND gate provides the false or low output only when their outputs is high or true. NAND GATE IS A UNIVERSAL GATE THE Application of nand Gate in. Your email address will not be published. But all you need to remember is that the only time the output of a NAND gate is 0 is when both the inputs are 1. As NOR gates are also functionally complete, if no specific NAND gates are available, one can be made from NOR gates using NOR logic.[1]. Digital systems employing certain logic circuits take advantage of NAND's functional completeness. The output state of the NAND gate will be low only when all the inputs are high. NAND Gate - An NAND gate, also called universal gate, is a gate that produces a logic "0" output only when all logic inputs are "1". When using static gates as building blocks, the most fundamental latch is the simple SR latch, where S and R stand for set and reset. A NAND gate is a universal gate, meaning that any other gate can be represented as a combination of NAND gates. In this NAND gate circuit diagram we are going to pull down both input of a gate to ground through a 1KΩ resistor. The truth table of two-input NAND gate is given below: In this Project NAND gate is made by combining AND and NOT Gate. NAND Gate is created by applying NOT operation to an AND gate. Applications of the NAND gate (a) Burglar alarm. Figure 1. Operation of the gate: a) A and B both low: both B-E junctions of Q1 are forward biased. Shown here are the logical method and the circuit through which one can obtain all the basic gates by only using NAND gates. The circuit output should follow the same pattern as in the truth table for different input combinations. In digital electronics, a NAND gate (NOT-AND) is a logic gate which produces an output which is false only if all its inputs are true; thus its output is complement to that of an AND gate. The circuit output should follow the same pattern as in the truth table for different input combinations. In this video we're going to build a two input multiplexer or two input digital mux made entirely out of NAND gates. The stored bit is present on the output marked Q. Apply "Set" Pulse: The time sequence at right shows the conditions under which the set and reset inputs cause a state change, and when they don't. Related Posts: The 7400 gates are 2 input NAND gates however 3 input NAND gates 7410 I.C., 4 input NAND gates 7420 and also an 8 input NAND gate 7430 can be also procured easily from the market. Circuit. By connecting them together in various combinations the three basic gate types of AND, OR and NOT function can be formed using only NANDgates, for example. A NAND gate (“not AND gate”) is a logic gate that produces a low output (0) only if all its inputs are true, and high output (1) otherwise. can be implemented using only NAND gates. Both AND Gate & NOT Gate is … We know that a half adder circuit has one Ex – OR gate and one AND gate. If you verify the output of the NAND gate circuit, you will find that it is same as the previous circuits created using basic logic gates. Practical Circuits Using NAND Gates. Because a NAND gate is nothing more than an AND gate whose output is inverted, you can create an AND gate from a NAND gate by inverting the NAND gate’s output. If both of the inputs are HIGH, both of the transistors will conduct through their collector-emitter paths, which creates a short circuit to ground. The NAND gate is the combination of the NOT-AND gate. If either of the 2 inputs are drawn HIGH (turned on), the output, the LED, will turn on. Let’s take a look at the symbol and the truth table. 12 Simple NAND Gate Hobby Circuits – Schmitt Trigger Circuits. It means all the basic gates such as AND, OR, and NOT gate can be constructed using a NAND gate. The NAND gate is a combination of an AND gate and NOT gate. If you were to remove the NOT gate from the circuit, you would have a SR flip flop. If the NAND gate is working correctly, output fis 0 and the led not burning. A Schmitt trigger is a quite simple kind of circuit, but it is amongst the most successful of all electronic building … Here first two transistor in series is used for making AND gate and the last transistor which is parallel with LED makes NOT Gate. A and B are two inputs while Y is the output. NAND gates are basic logic gates, and as such they are recognised in TTL and CMOS ICs. C. an OR gate. As long as the capacity of C is changed, square wave outputs of different frequencies can be obtained. A NAND gate is a digital circuit that has two or more inputs and produces an output, which is the inversion of logical AND of all those inputs. This is the circuit diagram of a NAND gate used to make work like a NOT gate, the original logic gate diagram of NOT gate is given besides the circuit diagram below. The output of the NAND gate is at logic 0 level only when each of the inputs assumes a logic 1 level. In TTL ICs using multiple-emitter transistors, it also requires fewer transistors than a NOR gate. They are connected in cascade form. Now let’s understand how this circuit will behave like a NAND gate. Although NAND gate seems to be the combination of two gates (one AND and one NOT gate), they are not. Basically, we use the first gate of the 4011 as the gate where we have our inputs. Required fields are marked *. Remember that this particular circuit can simply be developed employing a 4011 IC., as gate 4 must be a NAND type. Your email address will not be published. NAND gate symbol 2. As we know that NAND and NOR are called universal gates as any logic system can be implemented using these two, the half adder circuit can also be implemented using them. A NAND gate (sometimes referred to by its extended name, Negated AND gate) is a digital logic gate with two or more inputs and one output with behavior that is the opposite of an AND gate.The output of a NAND gate is true when one or more, but not all, of its inputs are false.If all of a NAND gate's inputs are true, then the output of the NAND gate is false. Both NAND and NOR has the ability to perform three basic logic functions such as AND,OR and NOT. The above diagram is of an OR gate made from combinations of NAND gates, arranged in a proper manner. It is also called Negated And gate. Full Adder using NAND Gates. {\displaystyle {\land }} The standard, 4000 series, CMOS IC is the 4011, which includes four independent, two-input, NAND gates. The truth table and equivalent gate circuit (an inverted-output NAND gate) are shown here: Of course, both NAND and AND gate circuits may be designed with totem-pole output stages rather than open-collector. This articles include Logic Gates-(NOT, OR, AND, NOR, NAND, X-OR, X-NOR GATE), PDF. This chip has 4 NAND gates in it. In this post we learn how to make simple and easy hobby circuits using any NAND gate IC such as IC 4011, IC 7400 or IC 4093. NAND gates can also be used to produce any other type of logic gate function, and in practice the NANDgate forms the basis of most practical logic circuits. The circuit uses two NAND gates set up as a latch that is being set or reset by the two touch sensors. One should know the fact that AND gate is constructed from the AND gate. Now let’s understand how this circuit will behave like a NAND gate. The next project uses two of the NAND gates on the 4011 to create an AND gate. The only difference is that instead of connecting the output to the emitter of the second transistor, the output is obtained before the collector of the first transistor. Whenever I see a new component I like to simulate it just to see how it behaves. NAND gate is the combination of AND gate and NOT gate. When using static gates as building blocks, the most fundamental latch is the simple SR latch, where S and R stand for set and reset. We can obtain NAND logic by just connecting a NOT gate to an AND gate. signifies AND and the bar signifies the negation of the expression under it: in essence, simply In this NAND Gate circuit I have used three Transistors. Hence the NAND gate is the inverse of an AND gate, and its circuit is produced by connecting an AND gate to a NOT gate.Just like an AND gate, a NAND gate may have any number of input probes but only one output probe. Because a NAND gate is nothing more than an AND gate whose output is inverted, you can create an AND gate from a NAND gate by inverting the NAND gate’s output. [Set up simulation with single NAND gate] When the two inputs are digital low, the NAND gate makes the input high. There are two universal gates NAND and NOR. In digital electronics, a NAND gate (NOT-AND) is a logic gate which produces an output which is false only if all its inputs are true; thus its output is complement to that of an AND gate. And the best way to do that is to just simulate it. {\displaystyle {\displaystyle \neg (A\land B)}} It can be constructed from a pair of cross-coupled NOR or NAND logic gates. For example, the function NOT(x) may be equivalently expressed as NAND(x,x). A NAND gate circuit that uses a CMOS logic chip. Contents hide 1. B Step 3: Construct the NAND circuit. In all the other cases, its output is high. If we want to perform n – bit addition, then n number of 1 – bit full adders should be used in the form of a cascade connection. The stored bit is present on the output marked Q. 3 NAND gates for OR gate circuit for X + Y’Z F= X + Y’Z. A NAND gate circuit that uses a CMOS logic chip. Circuit design OR Gate Using NAND Gate created by M Shahriar Ishtiaque with Tinkercad The circuit shown below is a basic NAND … A logic gate can be thought of like a light switch, wherein one position the output is off -- 0, and in another, it is on -- 1. A NAND gate circuit is almost identical to an AND gate circuit. The following chart is a equivalent to NAND You just need the original boolean expression then to convert to the equivalent NAND function. SR NAND latch. By De Morgan's theorem, a two-input NAND gate's logic may be expressed as AB=A+B, making a NAND gate equivalent to inverters followed by an OR gate. These are usually available in both through-hole DIL and SOIC format. A logic gate can be thought of like a light switch, wherein one position the output is off -- 0, and in another, it is on -- 1. Circuit design OR Gate Using NAND Gate created by M Shahriar Ishtiaque with Tinkercad With S and R both HIGH the NAND gates convert this to LOW at A and B. Basic logic gates. In all the other cases, its output is high. NAND gate. NAND gate is a combination of an AND gate and a NOT gate. Now we will go over how to build an OR gate from NAND gates. If you want to use NAND gates in a circuit, the CMOS IC 4011 contains 4 NAND gates. To build this you’ll need: An LED (L1) A chip with NAND gates such as the CD4011BE; 3 x 10 kΩ resistors (R1-R3) 2 x Two metal plates close together to create the touch sensor; Alternatives and Equivalents for CD4011 . Hence D1 and D2 will conduct to force the voltage at point C to 0.7V. We can derive logical function or any Boolean or logic expression by combination of these gate. Regarding the 7430, its 8 input gate will switch state only when each one of the 8 inputs are either 1 or 0. Only one type of gate is used in constructing the logic circuits which is an advantage in designing circuits. Half Adder using NAND Gates Five NAND gates are required in order to design a half adder. This is the circuit diagram of a NAND gate used to make work like a NOT gate, the original logic gate diagram of NOT gate is given besides the circuit diagram below. The Logic NAND Gate is generally classed as a “Universal” gate because it is one of the most commonly used logic gate types. D. ... Write the truth table for the circuits given in figure. The outputs of AND gate and NAND gates are inverse to each other. The next project uses two of the NAND gates on the 4011 to create an AND gate. ( The NAND GATE function can be expressed by the Boolean expression of Complement of A.B.The Boolean expressions of NAND gate along with their schematics symbol are shown in the following figure. If any one of the input is also high the output will be high that is 1. AND | OR | XOR | NOT | NAND | NOR | XNOR Diagram of the NAND gates in a CMOS type 4011 integrated circuit. AND gate and OR gate are simple light bubs switch circuits with 1 switch per input. The above diagram is of an OR gate made from combinations of NAND gates, arranged in a proper manner. The NAND gate is the universal gate. NAND gates with two or more inputs are available as integrated circuits in transistor-transistor logic, CMOS, and other logic families. ∧ We feed the output of this gate, which is pin 3, into the input of the second gate, which has shares a common signal because they're tied together. The NAND gate is essential because different types of a boolean function are implemented by using it. Since, in NAND gate logic, 2 LOWs give a HIGH as an output and 2 HIGHs as inputs give a LOW as output, it functions as a NOT gate in that it always gives the opposite logic state at the output than what is at the input. The NAND and NOR are also called as universal building blocks. This gate is also called as Negated AND gate. , where the symbol It is also called Negated And gate. Hence, the outputs of this gate are opposite to that of AND gate when the inputs are kept [[wysiwyg_imageupload::]]same. We do this by joining the inputs of the NAND gate, as seen on the next image. A LOW (0) output results only if all the inputs to the gate are HIGH (1); if any input is LOW (0), a HIGH (1) output results. Difference Between Electrical Energy and Electrical Power, Circuit Analysis of 3 Phase System â Balanced Condition, Two Wattmeter Method of Power Measurement, Difference Between Circuit Switching and Packet Switching, Difference Between Static and Kinetic Friction, Difference Between Ductility and Malleability, Difference Between Physical and Chemical Change, Difference Between Alpha, Beta and Gamma Particles, Difference Between Electrolytes and Nonelectrolytes, Difference Between Electromagnetic Wave and Matter Wave, Difference Between Kinetics and Kinematics. [1] An entire processor can be created using NAND gates alone. Since, there are 4 Logic gates, we will get 16 possible ways of realizing two level logic. Similarly, we can implement any Boolean function, which is in product of sums form by using NOR gates alone. You’ll find the truth table below. Here we are going to use 74LS00 IC for demonstration of NAND Gate. And then the inputs are connected to power through a button. A NAND gate’s output is low only when both the inputs are high. NAND-gate Latch. . The NAND gate is a combination of an AND gate and NOT gate. The above drawn circuit is a 2-input CMOS NAND gate. Two NAND gates are used as inverter at the input of the 3 rd NAND gate. MEDIUM. What is a NAND gate/NAND logic? Also, it is important to note that the inputs of the NAND gates are connected together; the same input. The NAND gate is a special type of logic gate in the digital logic circuit. Basically, we use the first gate of the 4011 as the gate where we have our inputs. NOT gate is a logic element whose output stage is always the complement of the input stage means when you supply logic 1 we will logic 0 and vice versa. OR gate operation needs three NAND gates. NAND gate Logic Symbol and equivalent circuit. Both NAND and NOR gates can perform all the three basic logic functions of AND, OR, NOT. A NAND gate’s output is low only when both the inputs are high. The NAND gate is significant because any boolean function can be implemented by using a combination of NAND gates. The only difference is that instead of connecting the output to the emitter of the second transistor, the output is obtained before the collector of the first transistor. NAND gates can build them all. The gate which can implement all the basic gates (AND, OR, NOT) as well as any gate and any circuit is called a universal gate. Types of Universal Gates NAND Gate (NOT-AND) NAND gate is a combination of AND gate and NOT gate. The NAND Boolean function has the property of functional completeness.This means, any Boolean expression can be re-expressed by an equivalent expression utilizing only NAND operations. Logic gates are commonly used in integrated circuits . A NAND gate is made using transistors and junction diodes. They are connected in cascade form. The following table shows the truth table of 2-input NAND gate. There are seven basic logic gates: AND, OR, XOR, NOT, NAND, NOR, and XNOR. A logic gate is a circuit with one or more input voltage In Figure 2 & 3, the NAND-based configuration was derived, the two possible inputs, zero and one, were tested, and the results were observed. I am opting to show the open-collector versions for the sake of simplicity. Truth be known it will require two I.C.s, since five gates are utilized in the circuit and only four are contained in each 4011 I.C. ∧ Basic logic gates consist of three basic logic gates namely NOT, AND and OR. It has the capability to perform the operations of 3 logic gates such as OR, AND gate and NOT gate. Actually, the NAND logic gate is not built by cascading an AND gate and a NOT gate, but it has an independent design. If the NAND gate is operating incorrectly, output fis 1 and the led is on fire. ) The above drawn circuit is a 2-input CMOS NAND gate. In our circuit, there will be 2 inputs. NAND gate is a combination of an AND gate and a NOT gate. You can use a NAND gate to build a simple burglar alarm that goes off when either the burglar’s shadow is detected, or the burglar stands on the pressure sensor present at the house entrance, or if both conditions are met simultaneously. Simple NAND Gate Circuit. The circuit diagram of a 2 input TTL NAND gate is as follows: A two input TTL NAND is shown above. If we connect the output of AND gate to the input of a NOT gate, the gate so obtained is known as NAND gate. It performs the function of OR, NOR and AND gate. Case-1 : VA – Low & VB – Low NAND and NOR gates are called universal gates. There are three symbols for NAND gates: the MIL/ANSI symbol, the IEC symbol and the deprecated DIN symbol sometimes found on old schematics. The NAND and NOR gates are the universal gates. ∧ With a 74LS00 the 4 NAND gates allow a single component to be used to create the gated latch. Now that you have gotten the boolean expression to the required standard, you can implement it as a NAND circuit. A NAND gate is a combination of an AND gate and NOT gate. It can be constructed from a pair of cross-coupled NOR or NAND logic gates. Note the truth table. This is because only NAND gate or only NOR gate can implement all the basic gates (AND, OR, NOT) as well as any gate and any circuit.These gates are widely used in digital circuits as these cost less to make. The NAND gate has the property of functional completeness. So when the button is pressed the corresponding pin of gate goes high. By De Morgan's theorem, a two-input NAND gate's logic may be expressed as AB=A+B, making a NAND gate equivalent to inverters followed by an OR gate. So first what is a digital mux. Last Updated on May 31, 2020 by admin Leave a Comment. Consider the four Logic gates AND, OR, NAND & NOR. That is still an illegal condition. Truth tables Electrical and Electronics Tutorials and Circuits NAND GATE. The concept of a "latch" circuit is important to creating memory devices. In the field of digital electronic circuits, this implies that we can implement any Boolean function using just NAND gates. For more information see logic gate symbols. Identify the logic operations (OR, AND, NOT) performed by the two circuits. These devices are available from most semiconductor manufacturers such as Fairchild Semiconductor, Philips or Texas Instruments. Why the NAND gate is so popular, because you can easily create every Logic Gate. The two NAND gates invert the input and then the inverted input is fed to the 3 rd NAND gate, which results in OR function as shown in figure below; AND | OR | XOR | NOT | NAND | NOR | XNOR consisting of NOR gates only. We can create a NOT gate using a NAND gate. The circuit schematic for an AND gate from a 4011 NAND gate chip is shown below. When all the inputs of a NAND gate are connected together, the resulting circuit is: A. a NOT gate. We feed the output of this gate, which is pin 3, into the input of the second gate, which has shares a common signal because they're tied together. When the LDR is in the light the other input is LOW. NAND gate. The truth table of the NAND gate is given below: From the truth table of the gate, it is clear that all the inputs must be high to get a low output and if any of the input is low, the output obtained will be high. NAND GATE IS A UNIVERSAL GATE THE Application of nand Gate in. Here, the outputs of first level Logic gates are connected as inputs of second level Logic gate(s). A 2 input gate will have 2 switches for inputs and 1 light representing the output. The function NAND(a1, a2, ..., an) is logically equivalent to NOT(a1 AND a2 AND ... AND an). The ANSI symbol for the NAND gate is a standard AND gate with an inversion bubble connected. Basic logic gates. Transcript. Save my name, email, and website in this browser for the next time I comment. SR NAND latch. Case-1: V A – Low & V B – Low. So lets explore the NAND gate a little bit. This circuit contains a 74LS00 Nand Gate integrated circuit. Here we use two NAND to create a clocked SR Latch. Among this circuit diagram: NAND gates 1, 2 and external RC time constant components form an oscillator circuit; NAND gate 3 is a buffer output stage. The output can only be low when both the inputs are high. There are seven basic logic gates: AND, OR, XOR, NOT, NAND, NOR, and XNOR. Their outputs is high and the best way to do that is 1 gate 4 be... Advantage of NAND gates are required in order to design a half adder, X ) May be expressed! Representing the output is as follows: a ) Burglar alarm just NAND gates in a manner... Y ’ Z performed by the two touch sensors a simple 1 – bit adder inputs a. 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With LED makes NOT gate operations ( OR, NOT, and NOT! This particular circuit can simply be developed employing a 4011 NAND gate essential... Voltage NAND gate in the field of digital electronic circuits, this implies we! 'S functional completeness significant because any boolean function using just NAND gates OR only gates... More input voltage NAND gate is operating incorrectly, output fis 0 and the truth table of NAND. Circuits single handedly derivation of the 3 rd NAND gate chip is shown.! Has 2 inputs behave like a NAND gate at every input level high is! Gate are simple light bubs switch circuits with 1 switch per input d.... Write the table! Certain logic circuits take advantage of NAND gate is ‘ — ‘ whole.... With s and R both high the NAND gates closed OR the light on! Above diagram is of an OR gate and NOT gate to ground through a button of. If you were to remove the NOT gate how to change a combinational circuit! Representing the output will be high that is 1, NOT, NAND NOR. Follows: a ) Burglar alarm consider the four logic gates, in. A and B transistor in series is used in constructing the logic circuit from and, NOT A.... Has the ability to perform the operations of 3 logic gates, we use first! Popular, because you can implement it as a NAND gate, gate., Philips OR Texas Instruments level logic gates ( NOT ) performed by the two circuits be employing. Low at a and B 2-input NAND gate… a NAND gate in will get 16 possible ways of two! To ground through a 1KΩ resistor gate is a universal gate, as on... Bit is present on the output of the NAND gates OR only NOR gates can perform all the other is... According to the equivalent NAND function going to use a separate 74LS08 circuit.