Electronics and Communication Engineering Digital Electronic Circuits Laboratory Experiments

Analysis and Synthesis of Boolean Expressions using Basic Logic Gates            

Procedure

Please follow these steps to do the experiment.

Part 1:

  1. At first go through the structure of 7404 Hex inverter, 7408(quad 2-input AND gates), 7432(quad 2-input OR gates).
  2. Next, apply a high level voltage to all the inputs A,B,C.
  3. Next, check that both LEDs glow. This is because both the outputs z1 and z2 attain the same value.
  4. Thus, AB+AC+BC=AB+AC holds for the condition A=B=C="1".
  5. For all the combinations of the variables A,B, and C verify that both the LEDs are glowing or not glowing. If the LED glows, it indicates that the corresponding output has reached logic 1 level. Similarly a dark LED indicates low level output voltage.

Part 2:

  1. At first go through the structure of 7400(quad 2-input NAND gates), 7408(quad 2-input AND gates), 7432(quad 2-input OR gates).
  2. Next, apply a high level voltage to inputs A,B.and apply low level voltage to the input C.
  3. Next, check that both LEDs glow. This is because both the outputs z1 and z2 attain the same value.
  4. So, the equivalence of AND-OR and NAND NAND structure can be verified.
  5. For all the combinations of the variables A,B and C verify that both the LEDs are glowing or not glowing. If the LED glows, it indicates that the corresponding output has reached logic 1 level. Similarly a dark LED indicates low level. output voltage.

Part 3:

  1. At first go through the structure of 7404 Hex inverter, 7408(quad 2-input AND gates), 7432(quad 2-input OR gates), 7400(quad 2-input NAND gates).
  2. Next, apply a high level voltage to all the Vcc inputs and keep low level voltage to all the Gnd inputs.If Vcc and ground are not connected properly then error message will be appeared and no output will be generated.
  3. Next, apply a high level voltage to the inputs A,B and apply low level voltage to the input C.
  4. Next, check that both LEDs glow.This is because both the outputs z1 and z2 attain the same value.
  5. Thus, AB+AC+BC=AB+AC =(A+C)(A+B) holds for the condition A=B="1" and C=D="0"
  6. For all the combinations of the variables A,B and C verify that both the LEDs are glowing or not glowing. If the LED glows, it indicates that the corresponding output has reached logic 1 level. Similarly a dark LED indicates low level output voltage

Part 4:

  1. At first go through the structure of 7402(quad 2-input NOR gates), 7408(quad 2-input AND gates), 7432(quad 2-input OR gates).
  2. Next, apply a high level voltage to all the Vcc inputs and apply low level voltage to all the Gnd inputs.If Vcc and ground are not connected properly then error message will be appeared and no output will be generated.
  3. Next, apply a high level voltage to all the inputs A,C and apply low level voltage to the inputs B,D.
  4. Next, check that both LEDs glow.This is because both the outputs z1 and z2 attain the same value.
  5. So, the equivalence of OR-AND and NOR-NOR structure can be verified.
  6. For all the combinations of the variables A,B,C and D verify that both the LEDs are glowing or not glowing. If the LED glows, it indicates that the corresponding output has reached logic 1 level. Similarly a dark LED indicates low level output voltage.