What kind of circuit is a zero crossing detector?
The zero crossing detector circuit is an important application of the op-amp comparator circuit. It can also be called as the sine to square wave converter. Anyone of the inverting or non-inverting comparators can be used as a zero-crossing detector.
Can a sine wave converter be used as a zero crossing detector?
It can also be called as the sine to square wave converter. Anyone of the inverting or non-inverting comparators can be used as a zero-crossing detector. The only change to be brought in is the reference voltage with which the input voltage is to be compared, must be made zero (Vref = 0V). An input sine wave is given as Vin.
What happens when optocoupler is on zero crossing detection?
When optocoupler is on, the output will be zero because output will be a ground reference. At zero crossing of a sine wave, optocoupler turns off and a pulse of Vcc magnitude appears at the output. Where to use zero crossing detection? We usually deploy these circuits with a microcontroller in power electronics projects.
How is zero crossing detected in a regenerative feedback circuit?
Thus zero crossing are detected for noise voltages in addition to the input voltage. These difficulties can be removed by using a regenerative feedback circuit with a positive feedback that causes the output voltage to change faster thereby eliminating the possibility of any false zero crossing due to noise voltages at the op-amp input.
How is zero detection realized on the mains side?
First of all the zero detection is realized on the mains side. The value of the capacitor C1 is important to obtain the desired output pulse. I would strongly discourage the use of transformer since the use of it creates a zero crossing not in sync with mains.
What is the input pin for zero crossing?
The other input pin#2 which is the inverting pin of ther iC is used for the zero crossing detection, and is applied with the preferred AC signal.