1. 9.5 555 Timer and Its Application 9.5.1 Circuit diagram ReturnNext

2. If V c1 and V c2 low level outputs happen at the different level of input signal, then input and output show Schmitt trigger characteristic; if it has a period after V c2 low level appearing,V c1 generate a low level output automatically, we name it as Monostable multivibrator; similarly if V c1 and V c2 low level outputs appear alternately, it’s a Astable multivibrator. NextBackReturn 555 timer consist of comparators C1 and C2, RS FF, open-collector transistor RSFF set 0 T on RSFF set 1 T off 9.5 555 Timer and Its Application

3. VIVI 0.01μF NextBackReturn 9.5 555 Timer and Its Application 9.5.2 Schmitt trigger using a 555 timer

4. Analysis: V I rising V c1 =1 V c2 =0 V o =1 V c1 =1 V c2 =1 V o =1 V c1 =0 V c2 =1 V o =0 V I falling V c1 = V c2 =1 V o =0 V c1 =1 V c2 =0 V o =1 The hysteresis is 9.5 555 Timer and Its Application

5. Monostable multivibrator using a 555 timer VIVI 0.01μF R C

6. 9.5 555 Timer and Its Application

7. Astable multivibrator using a 555 timer 0.01μF R1 R2 C

8. Charge time T 1 =(R 1 +R 2 )Cln2 Discharge time T 2 =R 2 Cln2 T=T 1 +T 2 =(R 1 +2R 2 )Cln2 q = T1/T=(R 1 +R 2 )/(R 1 +2R 2 ) Astable multivibrator using a 555 timer