Universal laboratory stirrer designed for simple stirring tasks for quantities up to 25 l (H2O). It automatically adjusts the speed through microprocessor controlled technology within the speed range of 0/30 - 2000 rpm. Safety circuits installed ensures automatic cut-off in an anti-stall or overload conditions. Continuous comparison of shaft speed to desired speed is maintained and variations are adjusted automatically. This guarantees a constant speed even with changes in viscosities of the sample.