The rectification operation is used in many nonlinear systems, such as those implementing fuzzy logic operations. This paper presents a very small current rectifier circuit which uses only three transistors to implement full-wave rectification. The low area-usage of the circuit allows it to be included in each processing cell of a large-scale, massively parallel, Cellular Nonlinear Network system, where the small area and low power consumption of building blocks is crucial. With the addition of current rectification, very efficient fuzzy processing functionality can be included in a grayscale CNN system.