Logic gates characteristics - Lab Report Example

Also, an XOR (Exclusive- OR) which is sometimes called an inequality comparator implements the expression such that “if A is different than B then X is true. Sometimes a buffer may be used between the inputs and output of a logic circuit. The buffer helps to increase the fan-in of the circuit. The XOR gate is commonly used as a buffer to supply a 0 or a1to one of its inputs. Multiplexers behave like rotary switches and select any one of its inputs as output. It is a combination of logic gates thereby having several inputs with only one output.

The input channel to be read into the output is controlled by supplying a definite digital word to the select inputs. In experiments using microelectronic chips such as the Multiplexer ICs, care should be taken when handling so as not to expose the chips to static hazards. The input lines to a multiplexer chip are 2, 4, 8 or 16 that supply the output one at a time. They are used to reduce the number of logic gates required to implement the circuit. Digital multiplexers are constructed from analogue switches encased in a single IC package.

The multiplexer is used in signal routing, data communications and data bus control. They can be used together with a demultiplexer to transmit parallel data in serial form through a single data link e.g. fibre optic cable. Multiplexers are also used a A/D converters thereby reducing the amount of heat dissipated (Bate, 1988). Aim To use a digital logic circuits to decode an industrial control system, and to test an equivalent logic decoding circuit using a multiplexer chip. Procedure The control system of a bottled water factory is designed to follow specific process to control the filling upon receiving specific instructions.

The process will halt with logic zero output. The processing plant sensors produce logic level outputs for the following devices. B – Bottle Position Correct Position= logic 1, and an incorrect position = 0 W – Water level low Water level low = logic 0, and water level satisfactory = 1 V – Flow Valve Position: Flow valve open = logic 0, and flow valve closed = 1 F – Water Filtration System: Filtration blocked= logic 0, and filtration working = 1 This process is halted on the following conditions: When the bottle position is incorrect and it is filling and this is indicated by an open flow valve.

Or if the water level is low, but not when the flow valve is open. Also, if the Filtration is blocked, but only if the Flow valve is closed and the water level is not low. Also, if the Flow valve is open, and if the bottle position is incorrect or water level remains low. Discussion Full truth table of the industrial control process is shown below; The above conditions for halting the process can be simplified as shown here under, Position, P = 0 if; 1). (B= 0).(V=0) 2). (W = 0) (V= 0) = (W = 0). (V= 1) 3) (F = 0). (V= 1). (W = 1) 4). (V = 0). (B = 0). (W= 0) P= X: (V=0). (W=1) Truth Table.

The above truth table can be simplified using the Karnaugh Map shown below; From the K- map it is clear that P = W.F. This can be implemented using the circuit shown below; B W V F P The circuit was built using the 74LS151 microchip as shown below and tested to find out if the desired result is obtained. The output Z was tested and found to follow the truth table shown here under, The tested output is found to quite agree with the results in the first truth table.