The BK Precision 1735A220V Single-Output Digital DC Power Supply, 30V/3A, 220VAC Line Input offers two 4-digit LED displays to continuously monitor voltage and current output. Connect two supplies in parallel to double the current output, or connect two supplies in series to double the voltage output. The circuit design incorporates a pre-regulator, which greatly reduces internal power dissipation at low output voltages. The 1735A-220V may be used in constant voltage or constant current applications. The crossover from constant voltage to constant current modes is smooth and automatic. LEDs indicate the "CV" (constant voltage) or "CC" (constant current) mode of operation.