EXPERIMENT # 09:
WORKING WITH MULTIPLEXER AND DEMULTIPLEXER
Logic ICs :
74LS139 (Dual 1-to-4 DEMUX)
74LS153 (Dual 4-to-1 MUX)
Connecting wires, etc
I have connected trainer to 220V AC power supply. Turned on the trainer, then I verified DC voltage by using voltmeter. I installed the IC 74LS153, on trainer. I wired the circuit by keeping in mind that all inputs and outputs are Active High. Then I supplied the data by switches and changed the select lines and inputs. Recorded the values and filled the table.
Then I disconnected the circuit, removed the IC and installed another IC 74LS139, again wired the circuit keeping in mind that inputs are Active High and outputs are Active Low. Then I supplied the data by switches and changed the select lines and inputs. Recorded the values and filled the table.
Faced bit difficulty in understanding IO high-low concept.
We were applying 5 volts but not getting them at the Vcc of IC.
Connecting wires we used was not properly inserted.
Checked the power supply for correct voltages.
Checked the Vcc (pin # 16) and ground (pin # 8) connection of given IC.
Checked all wires connections and removed any possible breaks.
Checked the IC under test for is proper working according to truth table.
For checking I used multimeter to measure voltage levels at inputs and
outputs of each gate in the chip.