The model H-25B Series high voltage power supplies are a versatile DC to DC converter series, designed for severe environment applications requiring a regulated high voltage source. The output voltage is directly sensed and can be adjusted over a 3 to 1 range by means of an output trim resistor.
The H25B series utilizes advanced high voltage techniques and compensation networks. All components are specially selected and burned in prior to assembly. The converter section uses rugged TO-5 transistors to insure a safety margin for secondary breakdown and leakage effects. In addition, the high voltage transformer is totally encapsulated with a low loss high temperature epoxy resin that guards against internal breakdown or corona.
The H-25B series is not restricted by orientation. Moreover, as the unit is hard potted, it does not contain oil that could leak out and damage other equipment.
The H-25B Series high voltage power supplies are specially designed linear regulator type power supplies. The normal input voltage of 24 VDC is stepped up by a push-pull oscillator to a high voltage output which is referenced to the input ground. The output voltage of the H-25B unit is NOT FLOATING. The output high voltage return and the input power return are internally connected together.
The output voltage may be controlled in two different ways. In the voltage programming mode, a control voltage between 0 - 5 VDC will adjust the output between 0 and full output. In the resistance programming mode, a resistor placed between the control voltage pin and ground will set the output to a voltage which depends on the value of the resistance used and the model number. Typically a 10-kOhm resistor will set the output voltage to 50%. Zero resistance yields full output for positive units.
Negative output units are available as well - for different types of detector sensing topologies. Here, the maximum output voltage is developed with the control wire open.
