Three imput logic gates multisim 14.1 plus#

Any of the inputs in the logic РІР‚СљHIGHРІР‚Сњ state will drive OR logic to the РІР‚СљHIGHРІР‚Сњ state.

The output of the logic OR is РІР‚СљLOWРІР‚Сњ when all of the inputs are in logic РІР‚СљLOWРІР‚Сњ states.

When all of the inputs are connected to ground OR logic goes РІР‚СљOFFРІР‚Сњ, turning the relay and lamp to РІР‚СљOFFРІР‚Сњ state. The relay thus turns on the lamp through an external circuit of 12V. The OR gate (74LS32) energizes the relay when any of its inputs is connected to VCC. In the following figure, an OR gate is used to drive a 12V relay to switch on the lamp using NI Multisim. The most commonly used OR logic packages are: CMOS based OR Gate IC Package The logic OR gates are available in both TTL and CMOS logic families. Figure 4: The OR logic having an odd number of inputs Commercially Available OR Gates It is explained in the following diagram where unused input is pulled down using a pull-down resistor. This will ensure that another input(s) of the logic OR gate is truly reflected at the output. The logic OR circuit having an odd number of inputs can be constructed by connecting the unused input to logic РІР‚СљLOWРІР‚Сњ.

The Boolean expression for this cascaded circuit can be written as: Q = (A + B) + (C + D) + (E + F) Odd Number of Inputs Figure 3: 6-input OR logic constructed by cascading multiple OR gates In the following figure, three two-input logic OR gates and one three-input logic OR gate are cascaded to construct a six-inputs (2 x 3 = 6) OR logic circuit. However, commercially available OR logic circuits have up to four inputs but the number of inputs can be further extended by cascading the OR logic circuits. The Boolean expression can be extended to include multiple inputs to obtain OR logic operation. Similarly, the truth table of a three-input OR logic gate is as follow: The truth table of a two-input OR logic gate is shown below: Its symbol denotes the addition/ OR logic operation. The representation of an OR logic by a symbol is shown in the following figure. A logic РІР‚СљHIGHРІР‚Сњ or +5V at any of the inputs will shift the relevant transistor from saturated РІР‚СљOFFРІР‚Сњ to РІР‚СљONРІР‚Сњ state and an output РІР‚СљHIGHРІР‚Сњ will appear across the resistor (R). The transistors are biased such that they operate in saturated РІР‚СљONРІР‚Сњ & РІР‚СљOFFРІР‚Сњ states. The inputs are connected to the base of transistors and output is taken from a common emitter/ across the resistor. Figure 1: The Resistor-Transistor Logic OR Gate The logic OR gate construction requires two Resistor РІР‚вЂњ Transistor Logic (RTL) connected in a parallel configuration as shown in the below figure. The logic OR gate can be constructed using the Resistor РІР‚вЂњ Transistor Logic (RTL) circuit. The РІР‚СљExclusive OR GateРІР‚Сњ will be discussed later in the article. The РІР‚СљExclusive OR GateРІР‚Сњ gives a false output when all of its inputs are at logic high. The logic OR gate gives a true output when both of the inputs are true and can be termed as РІР‚СљInclusive OR gateРІР‚Сњ. The addition (+) of anything with РІР‚Сљ1РІР‚Сњ will always be a РІР‚Сљ1РІР‚Сњ which simply expresses a logic OR gate. The logical OR expression with inputs A & B is given by: A + B = QР”Р„s in digital logic circuits, there are only two states i.e.

Three imput logic gates multisim 14.1 plus#

The Boolean expression of logic OR gate is that of a Logical Addition and is expressed by the plus (+) sign between the inputs (operands).

Similar to logic AND gate, the logic OR gate has a Boolean logic or expression. The logic OR gate gives an output of logic РІР‚СљLOWРІР‚Сњ only when all of its inputs are at logic РІР‚СљLOWРІР‚Сњ level and the output changes to logic РІР‚СљHIGHРІР‚Сњ at the instant state when any input changes from level РІР‚СљLOWРІР‚Сњ to РІР‚СљHIGHРІР‚Сњ. The logic OR gate can have multiple inputs and only one output. The logic OR gate gives an output of logic РІР‚СљHIGHРІР‚Сњ when any of its inputs goes to the РІР‚СљHIGHРІР‚Сњ logic level.