Multivibrator Electronic Post graduation topic, Study notes of Physics

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: ~ sero seerce ‘ 3a e& BF oe we espe HANDBOOK OF ELECTRONICS 630 , ID: : t " Vo = + Vsat | Bi Vea =a sa potential at point A ts Vor Ry + Ra ‘ si n e O be greater than Vpr- Ther output Now a pulse is given at R terminal of magn! ude at point B to be gr nm V, =~ Vsat If V_=— Vsat Roya) potential at point A is = Ry +Ra (= Vsav e y= d R= 1 output ts at If a pulse ts given to R-terminal then output Vo =— Veate b+ with §=0 an Reset state, i.e., 0 state (— Vear) Case (III); When S=1, R=0 If Vp = + Vsat R . ; potential at point A is = Rt Ry (4 Veqn) + pulse If a pulse is given to § terminal, potential at point A is more positive and hence output V)= + Vsat If V, = — Vat Ri potential at point A is = Ri+Rs (= Vsat) + pulse If the amplitude of the pulse is more than the negative potential at point A due to Vo =~ Vsat then resultant potential at point Ais positive, i.e. Vo= + Vat: Meo (45 to 15 volts) That is, with § = 1 and R=0, itis in Set state (1 state or + Vead- Case (iv): S=1,R=1, not used. 17.9.25 The 555 IC timer The 555 timer is an J C timer device. It can operate both as monostable and astable multivibrator. This monolithic device has ~ advantages over discrete circuits of monostable and astable multivibrator. Tt has fewer circuit connections and provides improved performance. It generates a pulse whose width can be varied by varying externally connected resistance and capacitance (Rand C7). Circuit of the 555 timer = {t can operate as an astable multivibrator or it can “T Threshold Comp. Discharge b—Oo Reset be triggered externally for monostable mode of operation. It has three inputs THRESHOLD: TRIGGER and RESET. These inputs control the states of the output —0 Output = Ground Fig. (75) Functional diagram of the type 555 IC timer. \ rr ee