The Brandenburg series 2478 is a range of high-performance power supply modules, designed to operate from a 24V (nominal) dc supply, with characteristics that make them ideally suitable for Photomultiplier Tube and similar applications. High efficiency, high frequency power conversion techniques are combined with a feedback-controlled regulation system using high-stability components, to give excellent regulation against changes in input voltage or load and a low output temperature coefficient, together with extremely low output ripple and noise. The output voltage is variable from 20% to 100% of nominal output, using a built-in potentiometer, and can be remotely programmed using either voltage or resistance programming. All models in the range are capable of delivering 10 W of regulated power at their full output voltage settings. The modules incorporate protection circuits which enable them to withstand arcs and short-circuits at the output without damage. Full encapsulation is used to give complete protection against humidity and a wide operating temperature range. Filtering of the input leads, and an aluminium housing, combine to cut off both conducted and radiated electrical noise. The MTBF of modules in this range is in excess of 100,000 hours at rated output.