Phys 351 lab 9

Phys 351 lab 9 - Peter Bohlen Lab 9 Digital Circuits Phys 117 Lab Section 457 Mondays 5-8 Honor Pledge Section A Gates Truth Tables and Pull-up

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Peter Bohlen Lab 9: Digital Circuits Phys 117, Lab Section 457, Mondays 5-8 Honor Pledge__________________
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Section A: Gates, Truth Tables and Pull-up Resistors A-1. The Inverter. - A clock input was applied to an inverter in the 7404 IC chip. The inputs and outputs were simultaneously viewed. The observed output is viewed below. - - Observing the inputs and outputs on the oscilloscope, it was noticed that the frequency was offset by 180 degrees, and the amplitudes were very similar, from 0V to 5V. The frequencies were alternated from 1kHz to 100kHz. The results were still the same, there was no observed timing problems. - Next Six inverters were wired in series with one another. The input of the 1 st and the output of the 6 th inverter were viewed simultaneously in order to view the propagation of delay. However, it was too hard to judge the propagation of delay on the output of the 6 th inverter because of the way they lined up. Therefore I measured the propagation of delay was measured off the output of the 5 th . The delay was measured to be 68ns going through all 5 inverters, so the delay for a single inverter was 68ns/5, or 13.6ns. - The clock was disconnected from the input, and the output from the 5 th inverter was hooked up to the input of the 1 st . Looking at the output of the 5 th on the oscilloscope, what appeared to be a cosine wave was viewed. - The wave had a measured frequency of 11.8MHz. The oscillations were caused by the 5 th inverter setting off the first, which then set off the second and so on. This continued to cycle around causing the oscillations. Had the 6 th inverter been hooked up to the first, nothing would have happened because they would not have been offset from one another. The predicted frequency is using the formula Frequency = 1/(Td*2*5) where 5 is the number of inverters the signal has to pass
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This note was uploaded on 11/03/2009 for the course PHYS 351 taught by Professor Staff during the Spring '08 term at UNC.

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Phys 351 lab 9 - Peter Bohlen Lab 9 Digital Circuits Phys 117 Lab Section 457 Mondays 5-8 Honor Pledge Section A Gates Truth Tables and Pull-up

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