The BK Precision Model 1743B220V Single-Output Digital DC Power Supply, 35V/6A, 220VAC Line Input operates continuously at full load without overheating, and offers constant voltage or constant current operation. The circuit design incorporates a pre-regulator, which greatly reduces internal power dissipation at low output voltages. The crossover from constant voltage to constant current modes is smooth and automatic, and indicated by LED's. Two supplies may be connected in series as a 0-to-70 volt power source, or two supplies may be connected in parallel, with suitable balancing resistors, for up to twice the output current.