Keithley Series 2200 USB and GPIB Programmable DC Power Supplies. The Series 2200 offers five models of DC power supplies with voltage outputs from 20V to 72V to address a wide range of power requirements. These supplies have both front and rear outputs for use on a bench or in a test system. With basic voltage setting accuracy of 0.03% and basic voltage readback accuracy of 0.02%, the voltage you program for the load is the voltage accurately applied at the output terminals. The rear panel connections include remote sense terminals that compensate for voltage drops in the power supply leads.