I. II. III. IV. ● Objective: Build and observe functioning of a S'-R' and S-R latches Build and observe functioning of a J-K flip-flop Parts List: S-R latch (Active-High Input): ● ● ● ● S'-R' latch (Active-LOW Input) ● ● ● ● J-K flip-flop: ● ● EET130 Digital Systems I Lab: Latches and Flip-flops 2 - 7402N Quad 2-input NOR gates 1 - 1 KOhm resistor 2- SPDT switches 2 - Digital probes 1- VCC (5V) 1 - GND ● 2- 7400N Quad 2-input NAND gates 1 - 1 KOhm resistor 2-SPDT switches 2 - Digital probes 1 - VCC (5V) 1 - GND School of Engineering Technology 2021 1 - J-K flip-flop 1 - 1 KOhm resistor 2-SPDT switches (to control preset and clear inputs) 1 - Clock voltage (to generate clock signal for flip-flop 2 - Digital probes 1 - VCC (5V) 1 - GND Procedures: Introduction: Both latches and flip-flops are considered as sequential circuits and can act as data storage devices. In these circuits current output depend on not only the current inputs but also on previous outputs. This experiment demonstrates the function of S-R and S'-R' latches as well as J-K flip- flops. 1. Construct the circuit shown in Figure 1(a) using components listed in parts list for S-R latch. 2. Change input S and R by changing SPDT switches and observe outputs Q and Q' using digital probes. 3. Write down results using Table 1. 4. Repeat steps 1-2 for S'-R' latch (Figure 1(b)). 1 5. Write down results using Table 2. 6. Construct the circuit shown in Figure 2 (top) using components listed in parts list for J-K flip- flop. 7. Change inputs preset and clear as shown in Figure 2 (bottom) and observe outputs Q and Q' using digital probes. 8. Write down results using Table 3. 0 0 1 S' 0 0 1 R R 0 0 (a) Active-HIGH input S-R latch (b) Active-LOW input S-R latch Figure 1: (a) S-R latch, (b) S'-R' latch 1 R' ē 1 School of Engineering Technology 2021 R Table 1: S-R latch results Q 2 Table 2: S'-R' latch results ē Q² Q' (a) (b) Clock 0 1 0 1 0 1 0 CLK PRE CLR Preset' 0 0 0 0 0 1 Preset HIGH J 3 K 1 1 1 1 1 Figure 2: J-K flip-flop Table 3: J-K flip-flop (' indicates bar) Clear' 1 School of Engineering Technology 2021 PRE 1 C CLR Q ē Toggle ♫ Clear Q² 1 0 1 0 1 0 1 0 1 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 4 1 1 1 0 0 0 School of Engineering Technology 2021