The sensor provides continuous, real-time, in-line viscosity measurements for in-line process control systems that requre high resolution and accuracy. The sensor is 1.3 x 1.1 x 0.4 in. and weighs only 4 oz. These viscosity sensors measure fluid viscosity from 1 to 500 centipoise and temperatures up to 125°C. They have an accuracy of 2%, reproducibility of 3%, and repeatability of 1%. They give a continuous audit trail for process monitoring to maintain quality standards and control operating costs.