1. Basic Operation of a 555 Timer Threshold Control Voltage Trigger Discharge Reset Output

2. Functional Diagram of 555 Timer

3. The 555 Timer Connected as a One-shot. Figure 8--49

4. One-shot Operation of the 555 timer. Figure 8--50

5. 555 Timer as a One Shot t w = 1.1R1C1 = 1.1(2000  )(1  F) = 2.2ms

6. 555 Timer as a One Shot waveform

7. Astable operation of 555 Timer t H =.7 (R1+R2)C1 =2.1ms t L =.7R2C1 = 0.7ms

8. Astable operation of 555 Timer

11. Less Than 50% Duty Cycle. Figure 8--54

12. Example 8-14. Figure 8--55

13. Astable operation of 555 Timer waveform

14. 555 Timer Datasheet