Pulse and Digital Circuits

16.3 555 TIMER APPLICATIONS

The 555 timer is another linear IC. The functional block diagram of a 555 timer is given in Fig. 16.13(a) and the pin diagram of a 555 timer is shown in Fig. 16.13(b). A 555 timer consists of:

1. A potential divider network comprising R₁, R₂ and R₃
2. Two voltage comparators
3. An R–S flip-flop
4. An inverting buffer output stage
5. Two transistors, Q₁ and Q₂

FIGURE 16.12(b) A bootstrap sweep generator using an op-amp voltage follower

FIGURE 16.13(a) The functional block diagram of a 555 timer; and (b) The pin diagram of a 555 ...