555 Pulse Generator

Sine Wave to Square Wave Converter Using the 555 Timer. The sinusoidal signal which has a negative and positive peak of -5 V and +5 V respectively is converted to 0 V to 5 V sinusoid and applied to the Threshold and Trigger input of the 555. The output goes low when the rising portion of the signal becomes greater than 2/3 Vcc. The output goes high when the falling portion of the signal becomes lower than 1/3 Vcc. Because of the symmetry of the input signal and the upper and lower switching levels the duty cycle of the output signal is almost 50%. The switching delay is noticeable in the graph however. Note: This is an inverting converter, at the positive alternation of the input signal the output goes low, at the negative alternation of the input signal the output goes high.