Different types of flow control valves are commercially available but most are only adequate for high flow rates. These are provided with pneumatic devices to reduce explosion risks in industrial plants. Flow-reduced and low pressure valves are small sized, usually driven by analogical signals and very expensive. Current assay developed an on-line computer-aided flow control electronic system made up of common electronic components within a comparative voltage scheme. A subtracted amplifier was employed in the electronic circuit which compares two voltages for rotation direction control and stoppage of speed engine reducer linked to the common valve stem. This low cost system is very efficient and has the advantage of being electronically assembled without any difficulty. Different sized valves were successfully coupled to the electronic circuit-driven reduction engine which provided flexibility to the developed apparatus. Calibration and time delay determination assays are provided, with lowest flow rates ranging between 0.3 and 3.6 mL s -1.332185189Antunes, A.J.B., Pereira, J.A.F.R., Fileti, A.M.F., Fuzzy control of a PMMA batch reactor: Development and experimental testing (2005) Computers and Chemical Engineering, 30 (2), pp. 268-276Delamarche, E., Juncker, D., Schimid, H., Microfluidics for processing surfaces and miniaturizing biological assays (2005) Advanced Materials, 17 (24), pp. 2911-2933El-Ali, J., Sorger, P.K., Jensen, K.F., Cells on chips (2006) Nature, 442, pp. 403-411Erickson, D., Li, D., Integrated microfluidic devices (2004) Analytica Chimica Acta, 507 (1), pp. 11-26Hosono, H., Satoh, W., Toya, M., Morimoto, K., Fukuda, J., Suzuki, H., Microanalysis system with automatic valve operation, pH regulation, and detection functions (2008) Sensors and Actuators B, 132 (2), pp. 614-622Silva, J.A.F., Lago, C.L., Electronic module for solenoid valve control (2002) Química Nova, 25 (5), pp. 842-843Weibel, D.B., Whitesides, G.M., Applications of microfluidics in chemical biology (2006) Current Opinion In Chemical Biology, 10 (6), pp. 584-591