SJTU Zhou Lingling13 The op-amp Differentiator Frequency response of a differentiator with a time-constant CR.
SJTU Zhou Lingling14 Bistable Circuit The output signal only has two states: positive saturation(L + ) and negative saturation(L - ). The circuit can remain in either state indefinitely and move to the other state only when appropriate triggered. A positive feedback loop capable of bistable operation.
SJTU Zhou Lingling15 Bistable Circuit The bistable circuit (positive feedback loop) The negative input terminal of the op amp connected to an input signal v I.
SJTU Zhou Lingling16 Bistable Circuit The transfer characteristic of the circuit in (a) for increasing v I. Positive saturation L + and negative saturation L -
SJTU Zhou Lingling17 Bistable Circuit The transfer characteristic for decreasing v I.
SJTU Zhou Lingling18 Bistable Circuit The complete transfer characteristics.
SJTU Zhou Lingling19 A Bistable Circuit with Noninverting Transfer Characteristics
SJTU Zhou Lingling20 A Bistable Circuit with Noninverting Transfer Characteristics The transfer characteristic is noninverting.
SJTU Zhou Lingling21 Application of Bistable Circuit as a Comparator Comparator is an analog-circuit building block used in a variety applications. To detect the level of an input signal relative to a preset threshold value. To design A/D converter. Include single threshold value and two threshold values. Hysteresis comparator can reject the interference.
SJTU Zhou Lingling22 Application of Bistable Circuit as a Comparator Block diagram representation and transfer characteristic for a comparator having a reference, or threshold, voltage V R. Comparator characteristic with hysteresis.
SJTU Zhou Lingling23 Application of Bistable Circuit as a Comparator Illustrating the use of hysteresis in the comparator characteristics as a means of rejecting interference.
SJTU Zhou Lingling24 Making the Output Level More Precise For this circuit L + = V Z 1 + V D and L – = –(V Z 2 + V D ), where V D is the forward diode drop.
SJTU Zhou Lingling25 Making the Output Level More Precise For this circuit L + = V Z + V D 1 + V D 2 and L – = –(V Z + V D 3 + V D 4 ).
SJTU Zhou Lingling26 Generation of Square Waveforms Connecting a bistable multivibrator with inverting transfer characteristics in a feedback loop with an RC circuit results in a square-wave generator.
SJTU Zhou Lingling27 Generation of Square Waveforms The circuit obtained when the bistable multivibrator is implemented with the positive feedback loop circuit.
SJTU Zhou Lingling28 Waveforms at various nodes of the circuit in (b). This circuit is called an astable multivibrator. Time period T = T 1 +T 2
SJTU Zhou Lingling29 Generation of Triangle Waveforms
SJTU Zhou Lingling30 Generation of Triangle Waveforms