Obtain the expression of Example 4-9 using a K map.

Data from Example 9

Refer to Figure 4-9(a). In a simple copy machine, a stop signal, S, is to be generated to stop the machine operation and energize an indicator light whenever either of the following conditions exists: (1) there is no paper in the paper feeder tray; or (2) the two microswitches in the paper path are activated, indicating a jam in the paper path. The presence of paper in the feeder tray is indicated by a HIGH at logic signal P. Each of the microswitches produces a logic signal (Q and R) that goes HIGH whenever paper is passing over the switch to activate it. Design the logic circuit to produce a HIGH at output signal S for the stated conditions, and implement it using the 74HC00 CMOS quad two-input NAND chip.

Figure 4-9

Transcribed Image Text:

Paper- sensing switches P Q R Feeder tray sensor +5V AND ||||| ΚΩ P R μα ΚΩ Logic circuit OR BD Q RO Q Re (b) (d) S-P+QR S-P+QR