The Fluke Model 408B High Voltage DC Power Supply is capable of providing an output of 0 to 6,000 Vdc at 0 to 20 mA. The output voltage is selected by four decade switches and a vernier potentiometer. The instrument may be operated with either positive or negative output terminal grounded, as selected by a front-panel switch. Overcurrent protection is provided to return the supply to standby operation in the event of excessive load current. The Model 408B is a hybrid design utilizing silicon transistors for the amplifier circuitry and a vacuum tube for the necessary high voltage series passing element. A time-delay relay is incorporated in the input circuitry, which prolongs the life of the high voltage passing tube. The reference element is a highly stable temperature compensated gas tube. SPECIFICATIONS Electrical OUTPUT VOLTAGE 0 to +/-6,000 VDC OUTPUT CURRENT 0 to 20 mA OUTPUT POLARITY + or - grounded via front panel switch LINE REGULATION 0.001% or 2 mV (whichever is greater) for 10% line change from nom