Objectives After completing this experiment you will be able

Objectives After completing this experiment, you will be able to: 1. Implement a traffic timing circuit with 555 Timer and HEF4017B 5 Stage Johnson Counter Materials Needed 1. 555 Timer 2. Various LEDs 3. 8 1N4148 Diodes 4. HEF4017B 5 Stage Johnson Counter 5. Resistors: 1 47KQ, 2 1000 Summary of Theory The following circuit of Fig. 12-1 provides a 4-way traffic light control for an intersection. The 555 timer is used to produce a pulse and control the HEF4017 B (Johnson Counter). Wire the circuit and demo it to your instructor. Then plot the LED output from each light for one cycle. Use the graph provided 16 4017 555 L14 NS 13 14 12 NS 1000 10on 1N4148 Figure 12-1 Diod

Solution

Ans). First of all 2nd image F package is the 555 timer used in the fig 12.1 and 3rd image is for stage 5 johnson counter. Q0 to Q9 and correspond pin number is 3, 2, 4, 7, 10, 1, 5, 6, 9, 11 decoded output. VSS pin number 8 ground supply voltage. Q5-9(bar) pin number12 carry output (active LOW). CP1(bar) pin number 13 clock input (HIGH-to-LOW edge-triggered). CP0 pin number 14 clock input (LOW-to-HIGH edge-triggered). MR pin number 15 master reset input.

You have to wire the circuit as shown in the fig 12.1 for the functioning of the whole circuit as traffic light control.

Pin number is also mentioned in the fig 12.1.

Clock (CP0 pin number 14 clock input (LOW-to-HIGH edge-triggered)) to the stage 5 johnson is comming from the 555 timer from pin number 3 and frequency is decided by the 47k ohm and 10uF.