The B & K-Predsion Model 1660 Triple Output DC Power supply is a high quality, general purpose dc power source. It provides two supplies with a 0-30 volt dc output and one with a 4-6.5 volt dc output. The 0-30 V supplies are adjustable with both coarse and fine voltage controls for precise settability and are capable of current output of 0-2 amps. The 4-6.5 V supply has a current output of 0-5 amps, allowing it to handle extensive digital logic circuitry. Two large panel-mounted LED meter displays can monitor either the output current or output voltage of each supply. The two 0-30 volt supplies can be operated independently or in one of two tracking modes. In the series tracking mode, the Slave supply tracks the voltage of the Master supply. Maximum current setting of the two supplies can still be set independently when in the series tracking operating mode. In the series tracking mode the Master and Slave supplies are connected in series, allowing a single output of 0-60 V at up to 2 amps. In the parallel tracking mode, the two supplies are connected together in parallel, allowing a single 0-30 V output at up to 4 amps. Both 0-30 volt supplies may be used in constant voltage or constant current applications. The crossover from constant voltage to constant current modes is smooth and automatic. LED's indicate the 'CV' (constant voltage) or 'CC' (constant current) mode of operation. In constant voltage applications, a current limit may be preset. When load variations cause the current to reach the preset limit, the unit then regulates output current rather than output voltage. Current limits are adjustable from 5% to 100% of maximum. In constant current applications, the maximum voltage may be preset. When load variations cause current to drop below the regulated value, the unit reverts to regulated voltage operation at the preset value. The 4-6.5 V supply is ideal for powering digital logic circuitry. The 0-5 amp capacity allows the supply to be used for large circuits. Built-in overload protection automatically limits to current output to a maximum of 5 amps. An indicator lights when the supply is overloaded. The Model 1660 exhibits excellent regulation and low ripple characteristics. The circuit design incorporates a pre-regulator, which greatly reduces internal power dissipation at low output voltages. Reverse polarity protection prevents accidental damage to the Power supply from improper connection to an external voltage, and current limiting protects the equipment being powered, as well as the Power supply. The output is isolated from chassis and earth ground, which permits full flexibility of connections. When needed, the (+) or (-) polarity may be strapped to ground, or either polarity may be floated to an external voltage. Additionally, the two 0-30 volt supplies can be used as a 'split supply' with two positive voltages and a common negative, two negative voltages and a common positive, or one positive, one negative, and a common. All of these configurations can be used with either matching (tracking) or differing (independent) voltages. The features and versatility of the unit, especially the triple output and tracking features, make it an ideal general purpose Power supply for engineering lab applications. It can serve as a single or multivoltage power source, including the bias supply, for breadboard and prototype circuits and equipment. It can provide single or simultaneously varying voltages for circuit evaluation. It can provide tracking (+) and (-} voltages for evaluating differential amplifiers. It may be used as a battery eliminator, or to power individual circuit boards or cards while removed from the system. Its output can be evaluated while powering a breadboard or prototype circuit to determine the circuit's Power supply requirements. Its laboratory quality specifications will meet most engineering laboratory requirements. The same features that make the Model 1660 a good choice for an engineering lab also make it a good choice for most other solid state electronic applications. These applications include service shops; industrial production testing of components, assemblies, and complete equipment; for school laboratories, and home use by electronic hobbyists.