Minor Project on Logic Gates

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  • Topic: Logic gate, XOR gate, Logic gates
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  • Published : April 30, 2013
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MINOR PROJECT|
DIGITAL ELECTRONICS|
|
THIS IS A REPORT BASED ON A PRACTICAL MODEL OF ELECTRONICS GATES.IT HAVR ALL THE INFORMATION ABOUT ALL BASIC GATES WHICH WE HAVE USED IN A PROJECT.| |
HIMANSHU GROVERMANISH THAKURKHUSHBOO VERMA|
15/04/2013|
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OR GATE
The OR gate is a digital logic gate that implements logical disjunction - it behaves according to the truth table to the right. A HIGH output (1) results if one or both the inputs to the gate are HIGH (1). If neither input is HIGH, a LOW output (0) results. In another sense, the function of OR effectively finds the maximum between two binary digits, just as the complementary AND function finds the minimum. TRUTH TABLE

INPUTA B | OUTPUTA + B|
0 0| O|
0 1| 1|
1 0| 1|
1 1| 1|

HARDWARE DISCRIPTION AND PINOUT
OR Gates are basic logic gates, and as such they are available in TTL and CMOS ICs logic families. The standard 4000 series CMOS IC is the 4071, which includes four independent two-input OR gates. The traditional TTL version is the 7432. There are many offshoots of the original 7432 OR gate. All have the same pinout but different internal architecture, allowing them to operate in different voltage ranges and/or at higher speeds. In addition to the standard 2-Input OR Gate, 3- and 4-Input OR Gates are also available. In the CMOS series, these are: * 4075: Triple 3-Input OR Gate

* 4072: Dual 4-Input OR Gate
TTL variations include:
* 74LS32: Quad 2-input OR gate (Low power Schottky version) * 74HC32: Quad 2-input OR gate (High Speed CMOS version) - has lower current consumption/wider Voltage range * 74LVC32: Low voltage CMOS version of the same

There are three symbols for OR gates: the American (ANSI or 'military') symbol and the IEC ('European' or 'rectangular') symbol, as well as the deprecated DIN symbol.[2][3] For more information see Logic Gate Symbols

MIL/ANSI SYMBOL

IEC SYMBOL

AND GATE
The AND gate is a basic digital logic gate that implements logical conjunction - it behaves according to the truth table to the right. A HIGH output (1) results only if both the inputs to the AND gate are HIGH (1). If neither or only one input to the AND gate is HIGH, a LOW output results. In another sense, the function of AND effectively finds the minimum between two binary digits, just as the OR function finds the maximum. Therefore, the output is always 0 except when all the inputs are 1s. TRUTH TABLE

INPUTA B| OUTPUTA AND B|
0 0| 0|
0 1| 0|
1 0| 0|
1 1| 1|

If no specific AND gates are available, one can be made from NAND or NOR gates, because NAND and NOR gates are considered the "universal gates," [1] meaning that they can be used to make all the others. XOR Gates can also be used to simulate AND functions, but are rarely used to do so.

MLI/ANSI SYMBOL

IEC SYMBOL

AND GATES USING DIODE

NOR GATE

The NOR gate is a digital logic gate that implements logical NOR - it behaves according to the truth table to the right. A HIGH output (1) results if both the inputs to the gate are LOW (0); if one or both input is HIGH (1), a LOW output (0) results. NOR is the result of the negation of the OR operator. It can also be seen as an AND gate with all the inputs inverted. NOR is a functionally complete operation—combinations of NOR gates can be combined to generate any other logical function. By contrast, the OR operator is monotonic as it can only change LOW to HIGH but not vice versa. In most, but not all, circuit implementations, the negation comes for free—including CMOS and TTL. In such logic families, OR is the more complicated operation; it may use a NOR followed by a NOT. A significant exception is some forms of the domino logic family. The original Apollo...
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