The valve mode is the most common operational mode of magnetorheological fluid (MRF) devices in engineering applications. Magnetorheological (MR) valves have been studied upon their self-sensing capabilities resulting from the electromagnetic induction phenomenon. In parallel, studies have been carried out regarding the microstructural properties and the analytical modeling of MRFs used in valves. This paper presents the design and fabrication of a microfluidic system in the form of a magnetic circuit, consisting of a MRF flow channel, with dimensions close to those of previously studied miniaturized MR valves. The channel is enclosed in ferromagnetic and transparent sheets. The sheets facilitate the magnetic field distribution, created by a coil. The channel allows the microscopical MRF particles observation and their correlation with the MRF magnetic and rheological properties when the self-sensing phenomenon occurs.