This Regulated DC Power Source is suitable for general purpose laboratory and industrial applications. Each unit contains two sources in a single case. Each source may be operated independently or combined in a series of parallel arrangement. In addition each output may be operated in either the constant voltage or constant current mode. Transfer from constant voltage to constant current or visa versa is automatic. A current mode iamp indicates when the constant current mode is in operation. Metering is provided by means of two separate digital panel meters. The meters are switch selectable for monitoring the output voltage or current of each source. The Models TW347D and TW605ÖD include a front panel adjustable crowbar that protects load circuits against overvoltage conditions. The Model TW347D features a switch selectable tracking mode of operation. When the front panel switch is set for tracking there is an internal connection between both outputs and source B tracks source A to within 10 millivolts with a single control Two ten-turn potentiometers in each source provides voltage and current control with high resolution.