Discuss the Dynamic Operation of Logic Gates

Dynamic Operation of Logic Gates

Dynamic Operation of Logic Gates

Discuss the Dynamic Operation of Logic Gates. Logic gates are devices which are idealized as physical devices to digital circuits. This logic circuit performs the basic logic functions that form the basis of digital circuits. Logic gates are used in the devices we use nowadays such as computers and memory devices. Circuit logic gates make decisions based on a set of digital signals that come from their inputs.

Many of the logic gates have two inputs and one output. Logic gates are based on Boolean algebra. Each step is either in the false or true state of the two binary options. False represents 0, while true represents 1. Depending on the type of logic gates or inputs used , the binary output will change accordingly . The output of the logic gate is 0 in one position and 1 in the other position similar to the light switch. They can be termed as integrated circuits.

Combinations of these logic gates can perform many operations.  The total number of gates that can be arranged in an array and used in one device is theoretically unlimited.  The number of gates that can truly fit into a given physical location is limited.  In digital integrated circuits, there are arrays of logic gates.

AND Gate

The AND gate is known, so if 0 is called ‘false’ and 1 is called ‘true’, then the gate works the similar way as the logical ‘and’ operator.

OR Gate

The output is “true” on the OR gate if one or both inputs are “true”. If both inputs are “false”, the output is “false”. In other words, for having the  output to be 1, the input must be at least one or two 1s.

XOR Gate

An XOR (exclusive OR) gate is identical to an “either/or” gate. The output is “true” if either input, but not both, is “true”. The output is “false” if both inputs are “false” or if both inputs are “true”. In other words, the output is 1 if the inputs are different, but 0 if the inputs are the same.

NOT Gate

The logic inverter, sometimes called a NOT gate to distinguish it from other types of electronic inverter devices, has a single input. Reflects the logical state. If the input is 1, the output is 0. If the input is 0, the output is 1.


The NAND gate acts as an AND gate followed by a NOT gate. It behaves in the manner of the logical process ‘and’ followed by negation. The output is “false” if both inputs are “true”. Otherwise, the output is True.

NOR Gate

A NOR gate is a composite OR gate followed by an inverter. Its output is “true” if both inputs are “false”. Otherwise, the output is true.


An XNOR (Exclusive-NOR) gate is a composite XOR gate followed by an inverter. Its output is “true” if the inputs are the same and “false” if the inputs are different.

NOT gate
NOT gate

The Node between the two gates is labeled A because it is distributing the capacitive load to both. Two types of material overlapped between them. The presence of stray capacitance has a negative effect on the running speed logic circuits.

The voltage across the capacitor cannot change instantly. Time for the charge or discharge of the capacitor depends on the size of the capacitance C and the quantity of the current through the capacitor. When the PMOS transistor is in N1 is turned on, the capacitor is charged to VDD; It is discharged at the NMOS transistor running.

In each case, the identifier of the current flowing through the embedding transistor and the value from C determines the rate of charge and discharge of the capacitor.

charge and discharge of capacitor
charge and discharge of capacitor

This equation tells us the speed of the circuit depends upon both the values. The expression show the time of propagation when the output changes from high level to low level. The low to high level is also given by the above equation .In logic gates we usually set the value of L to minimum level for the specification required. The value of W is chosen according to the amount of current flow

There is a particular method involved in choosing transistors sizes because a larger transistor takes more space on the chip rather than the other one. The proportionality of C to the W and L tends to improve the expected performance. They are utilized where high capacitive loads must be driven and and signal propagation must be delayed accordingly.

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