A low cost, still versatile instrument for kinetic analyses with the variable time approach is described. Signals changing with a rate of a few mV/s up to tens V/s can be handled and time intervals in the range of a few ms up to 1000 s can be measured with a precision better than 0.2% in most cases. Data for the kinetic determination of creatinine in urine by spectrophotometry and potentiometric monitoring and of ascorbic acid by a stopped-flow spectrophotometer are presented to demonstrate the capabilities of this instrument.