Designed primarily as a high voltage photomultiplier power supply with a 15-0-15 volt auxiliary low voltage supply, adjustable between 5 V and 15 V, for transistor circuitry. 220 mA capability permits operation of most amplifier/discriminator units. • provided with high tension plug and lead pre-wired for output polarity specified at time of order and mating connector for the low voltage output facility. • instant switch-on without 'spikes' or surges ; ': • 100 V to 2800 V at 5 mA max. • adjustable to within 0.2 V • digital dial fine voltage control • very low ripple • reversible output polarity • compact and highly stable • option for programming • option for 19" rack adaption Description The output range provided by this unit is 100 volts to 2800 volts. Any voltage within these limits can be set by means of a 12 position switch with 200 volt steps and a 3 digit indicating dial controlling a 5-turn potentiometer giving 0-500 volts above the switch setting. Polarity is determined by the specially wired connecting lead provided. This is a convenient and safe method of permanently determining the polarity applied to a photomultiplier and obviates the dangers inherent in other methods of selecting polarity. The advanced specification and very economical price have been achieved by the use of all solid state linear circuit techniques which develop the high voltage without the 'spikes' and high frequency noise usually associated with inverter or saturated core devices. Excellent line and load regulation has been achieved by careful design. Ripple is less than 2 mV at full output; voltage change with temperature is negligible. A standard feature of the unit is the provision of a low voltage auxiliary power supply with adjustable outputs for use with a wide range of photomultiplier head amplifier circuits. The positive and negative auxiliary power supply outputs are independently adjustable between 5 V and 15 V via rear panel pre-set controls. All the power supplies necessary to operate a photomultiplier light detecting system have therefore been conveniently contained in a single unit. Applications This unit has a wide voltage range sufficient to suit the majority of photomultiplier tubes from side window types to fast linear focused structures. Dependent upon individual dynode chain currents, more tttan one photomultiplier may be driven from the same supply provided the maximum supply current is not exceeded. The unit is designed as a laboratory power supply and will find many other applications where a high voltage, precision supply is needed.