basic diagram thereof is shown in fig3 in fig3 an input voltage ui is compared with two switching thresholds u1 and u2 of two comparators k1 and k2 outputs of the comparators respectively control set and reset inputs of a flip flop ff while the configuration of fig3 is improved over the schmitt trigger of fig2 because the switching thresholds are precisely defined nevertheless the function of the circuit in the event of problems such as signals contaminated with noise or upon fluctuations in the internal supply voltage or in the event of externally coupled in signals is not reliably assured for example at a predetermined input signal ui and a brief reduction in the positive supply voltage or a brief rise or increase in the reference potential the switching thresholds of the comparators can be influenced in such a way that one of the comparators will already be made conducting even though the switching point for unimpeded operation has not yet been reached in fig1 an input signal terminal in is connected to one terminal of each of two transistors t1 and t2 acting as transfer gates the transistor t1 is controlled by a positive supply potential vdd and the transistor t2 is controlled by a negative supply potential vss other output terminals of the transistors t1 and t2 which are located in the signal direction are connected to one another and are also connected to an input e1 of an inverter i1 to an input e2 of an amplifier v2 and to a control input of a transistor t3 output terminals of the transistor t3 are connected to one another and to the supply potential vss output terminals of the inverter i1 and the amplifier v1 each control one input of a flip.