The regulated DC power supply of C-SERIES is designed to be used in applications such as powering operational amplifier, pushpull stages, logic circuit and definition systems where plus and minus voltages are required to track with an insignificant error, and in any application where three independent power supplies housed in a single package represent an oprating convenience. The instruments consist of two identical, independdently adjustable DC power supplies. A front panel switch selects one of three modes of operation: independent, series and parallel. In the independent mode, the output voltage and current of each supply are controlled separately, and each supply is isolated up to 300V from output to chassis or output to output. In the tracking mode, both outputs are automatically connected in series or parallel, and the controls of the left supply adjust the magnitudes of both the positive and negative output voltages. Because the outputs are connected in a tracking configura tion, any internal disturbance in the master supply {such as drift or ripple) will cause an equal percentage change in the outputs of bothe the supplies. Each power supply (except fixed 5V) is a completely transistorized, well-regulated, constant voltage/constant current suply that will furnish full rated output voltage at the maximum output current or can be continuously adjusted throughout the output range. The front panel current controls can be to establish the output current limit (overload or short circuit) when the supply is used as a constant voltage source (independent or tracking modes) and the voltage controls can be used to establish the voltage limit (ceiling) when the supply is used as a constant current source (independent mode only). The supply will automatically cross over from constant voltage to constant current operation (current limited operation in the tracking mode) and vice versa if the output current or voltage exceeds these preset limits. Each supply had its own front panel meter that can measure output voltage or current. One power supply may be used as a master supply controlling, one slave supplies furnishing various voltages or current for a system. When operated with the front panel mode switch in the tracking position, the instrument is automatically internally connected is autotracking configuration. For audio production line, the continuous or dynamic load internal selectable. When the connector (J111, J611) it was connected to "ON” position suitable for audio power Amplifier application (Normal setting to "OFF" position).