The Differentiator of Slowly Varying Electrical Signals

This paper describes the theoretical foundations, design, construction and testing of a new differentiator especially useful for differentiating slowly-varying electric signals. The differentiator employs a feedback loop with a nonlinear element for generating pulses whose mean value is proportional to the input signal derivative. The practical system was constructed by using three operational amplifiers and gave a possibility to achieve a differentiating time constant of about 106 s. The differentiator finds a special application for thermal processes controlling.