The Integrator is a type of Low Pass Filter circuit that converts a square wave input signal into a triangular waveform output. As seen above, if the 5RCtime constant is long compared to the time period of the input RC waveform the resultant output will be triangular in shape and the higher the input frequency the lower will. The Differentiator is a High Pass Filter type of circuit that can convert a square wave input signal into high frequency spikes at its output. If the 5RCtime constant is short compared to the time period of the input. If we now change the input RC waveform of these RC circuits to that of a sinusoidal Sine Wave voltage signal the resultant output RC waveform will remain unchanged and only its amplitude will be affected. By changing the. where RC is the time constant of the circuit previously defined and can be replaced by tau, T. This is another example of how the Time Domain and the Frequency.