Laboratory 8 Daniel Choi 904169062 Sec 2a a We will create an on off logic switch with an LED We build the circuit as below The SPDT single pull dual throw switch needs 3 connections When the switch is on channel 1 5V the LED turns on and when put to channel 2 0V the LED turns off This happens because the switch will connect the LED to power when thrown to channel 1 b We take the CMOS NOR MC14001B CMOS NAND MC14011B and TTL XOR MC74F86 chips We following circuits and truth tables with corresponding pictures depict the logic of the chips respectively Seen throughout the lab report A will be our input1 B will be our input2 and Q will be out output 1 will correspond to 5V on and 0 will correspond to 0V off Figure 1 2 3 4 A red 1 0 1 0 B blue 1 1 0 0 Q green 0 0 0 1 Figure A red B blue Q green 5 1 1 0 6 1 0 1 7 0 0 1 8 0 0 1 Figure 9 10 11 12 A red 1 1 0 0 B blue 1 0 1 0 Q green 0 1 1 0 13 2 c We will now build a both and either or and a XOR logic gates only using CMOS NAND s a Both using NAND s to make an AND b Either using NAND s to make an OR c XOR using NAND s to make an XOR 14 1 S R Latch d We will build an S R latch using the Dual NOR 74HCT02 chip as below The crossing lines are not connections e We experiment with the S are R switches and see how they affect Q by observing LED s that are connected to each switch This is called an SR latch because the S stands for SET and the R stands for RESET This means that one switch that is connected as the SET switch will memorize what you did on the circuit The RESET will then clear this memory The memory state or SET and RESET are seen in our figures below 14 2 D type flip flop f We take our D type flip flop 74HCT72 chip We plug the numerous pins as following We then mess with our D data and Clk clock and how they affect the output Q Figure D red Clk blue Q green 0 0 0 1 0 1 1 1 1 0 1 1 0 1 0 1 1 0 Description We see that the clock is what remembers what the output is regardless of what we do to D We now plug in our RESET pin 1 into 0V and we see that our clock doesn t work as it did before Figure D red Clk blue Q green Description 1 0 1 Our clock should memorize our output keep it on 1 1 0 When we turn on our clock our Q comes out to be 0 Now we plug both out RESET pin 1 and out SET pin 4 to 0V We see that our output Q is 1 no matter what we do to our D and Clk switches Figure D red 0 1 0 1 Clk blue 0 0 1 1 Q green 1 1 1 1 Now we release both SET and RESET We see that sometimes it works and sometimes it doesn t This occurs because it is in an undefined state g We set D to 1 and the clock to 1 Q is now 1 We changed our D to 0 and we turn the clock to 0 Our Q did not change to 0 as it should Now we set our clock to 1 while our D was 0 Q now changed to 0 We then changed D to 1 and nothing happened We now change our clock to 0 We change our D and still nothing happens Only when we change our clock from 0 to 1 do we see a change in our Q The clock only works when it is switched from 0 to 1 the rising edge It does nothing when it goes from 1 to 0 falling edge h We now add a 1 F capacitor in parallel with the output We see that the bounciness disappears when we add the capacitor i We take a seven segment common cathode without decoder and we want to make a 0 The drawing below shows the connections of each pin We plug in pin 3 to ground across a 270 resistor and to make a 0 we plug pins 1 2 4 6 7 and 9 into 5V k We now hook up a decade counter chip to our breadboard CD4026 and connect the correct pins such as the following drawing We use our square wave generator as the input clock changing from 0V to 5V We use the scope to observe what is going on We see that there are 5 instances where the voltage is high 5V and 5 instances where the voltage is low 0V This shows that for counts 0 4 it is high and for counts 5 9 it is low figure We now take the input and connect it to the switch that we built in part b We play with it with and without debouncing Without debouncing when we flip the switch imitate the function generator we see there are these crazy lines on our output of our scope These are the times when the switch is in between the 5V and 0V Figure Now when we put a capacitor in parallel with the output and we do the same thing Now all of the crazy lines disappear and there is a rise and drop in our voltage only when we flip the switch figure l Now we hook up the CD4026 chip s drivers to the 7 segment common cathode LED numeric display correctly connecting the proper pins and clock the chip at 1Hz using our function generator We see that the counter clocks slowly from 0 to 9 and this keeps going on As we increase the frequency the numbers increase at a faster rate