Name– study of RS flip-flop using NAND gates and NOR gates.
Aim – to study the working of RS flip-flop using NAND gates and NOR gates and compare them.
Apparatus – IC 7400, IC 7402, circuit board, power supply +5V DC, LEDs, connecting wires, soldering iron, cutter etc.
Circuit diagrams
[attachment=13816]
[attachment=13817]
Procedure –
1) You are given IC 7400 and IC 7402. Identify the ICs by reading their numbers and details from above given pin configurations.
2) Connect the gates with their respective pin numbers to construct the circuits of RS flip-flop using NOR gates & NAND gates as shown in the circuit diagrams.
3) Connect final outputs of the circuit to the LEDs.
4) Verify the truth table for each combination of inputs R & S, by giving different combinations of logic inputs as shown the respective truth tables.
5) Write the observed truth tables and compare them with theoretical truth tables.
6) Compare the truth tables of both flip-flops and write the difference.
Brief theory –
RS Flip-flop using NOR gate – consider the above left-side circuit. Here two NOR gates are used such that the output of one is the input of other. Also, one input of each gate is taken out as SET and RESET. The two outputs are Q and .
[attachment=13818]
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Conclusion –
1) In above flip-flops, the first and last states of outputs are interchanged.
2) In RS flip-flop using NOR gates, the initial state of the circuit is called LAST STATE.
3) In RS flip-flop using NAND gates, the initial state of the circuit is called FORBIDDEN STATE.
4) In both types of flip-flops, the output Q follows the state of input S and output follows the state of input R.