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Zero Crossing Detector

2018-01-31 02:24  
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Zero Crossing Detector using 741 IC

Zero Crossing Detector using 741 IC

How to make a Zero Crossing Detector using 741 IC ?

Zero-crossing detectoris an applied form of comparator. Either of theop-amp basic?comparatorcircuits discussed can be employed as the zero-crossing detector provided the reference voltage Vrefis made zero.?Zero-crossing detector using inverting op-amp comparator is depicted in figure. The output voltage waveform shown in figure indicates when and in what direction an input signal vincrosses zero volt.?In some applications the input signal may be low frequency one (i.e. input may be a slowly changing waveform). In such a case output voltage vOUTmay not switch quickly from one?saturation state to the other. Because of the noise at the input terminals of the op-amp, there may be fluctuation in output voltage between two saturation states ( Vsatand – Vsatvoltages). Thus zero crossings may be detected for noise voltages as well as input signal vin. Both of these problems can be overcome, if we use regenerative or positive feeding causing the output voltage voutto change faster and eliminating the false output transitions that may be caused due to noise at the input of the op-amp.

zero crossing detector waveform

zero crossing detector waveform


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