op-amp as compatator

Sine to Square Wave Converter Using an Analog Comparator. This circuit is intended for single-supply comparators. When using a comparator powered from a bipolar supply, a sine wave can be converted to square wave by simply using a zero crossing detector. For single-supply operation, a voltage divider biases the reference input and the sinusoidal input signal which has a negative and positive peak of -5 V and +5 V respectively is first converted to 0 V to 5 V sinusoid before feeding to the comparator.