Abstract: This operational amplifier has an output range comprised between values adjustable as desired and includes a differential input stage and an output gain stage, and two additional differential stages supplied at one input with the output voltage of the operational amplifier and at the other input each with a reference voltage representing either the upper limit or the lower limit of the sought range. The outputs of the two additional differential stages are connected to the input stage of the operational amplifier such as not to interfere with the latter when the output voltage of the operational amplifier is comprised between the range limits and to allow switching off and functional substitution of the input stage for either differential stage when the operational amplifier output is equal to the reference voltage of this differential stage, so as to hold that reference voltage at the operational amplifier output regardless of the signal at the input to the operational amplifier.