The PE 1540 is a 120 W stabilized power supply designed for supplying and testing electrical and electronic circuits. Regulation is achieved in two stages; a thyristor pre-regulator and a transistor series-regulator stage. By means of thyristor pre-regulator optimum efficiency can be obtained and a favourable relation between dimensions and delivered power is obtained.The transistor series-regulator gives continuously variable adjustment of the output voltage and current with good accuracy and stability with minimum ripple.