Squarewave generators employing OTRAs

Two squarewave generators consisting of only one operational transresistance amplifier and minimum external passive elements are presented. The first circuit is a general multivibrator that can produce an approximately symmetrical squarewave with a fixed duty cycle and a variable frequency. The second one can further independently control the on- and off-duty cycles of a squarewave by adjusting the values of the passive elements. These proposed squarewave generators are described and analysed. The experimental results and the recorded waveforms confirm the theoretical analysis and verify the feasibility of the presented schemes.