Abstract: A method of and apparatus for treating with a liquid a sheet of flexible photographic material having a photographic emulsion on one face thereof are described. The sheet of photographic material is introduced into a processing vessel (2) from above the liquid in the vessel and into the liquid with the other face of the photographic material directed to the inner wall of the vessel and the emulsions surface directed to the interior of the vessel. The sheet is driven along a curved endless path within the vessel by passing the sheet through the nips between at least one pair of driven rollers (9 and 12, 13 and 14) and is guided so as substantially to follow the inside wall of the vessel (8) during its passage through the liquid, whereby the emulsion surface cannot come into contact with a stationary part of the vessel and will not therefore be damaged during the treatment in the liquid.

Abstract: A stabilized power supply which is particularly suitable for use at very high voltages derives its energy from a resonant inverter feeding a transformer and rectifier. The power supply is intended to be operated in a pulsed mode with the generation of each pulse reducing the output voltage below its required value. The output capacitive stages of the power supply are subsequently re-charged and an input switch is rendered non-conductive when the output voltage regains its required value. As it is not possible to switch off a resonant inverter during the course of a cycle, the energy obtained from the inverter during the remainder of the current cycle is fed into another capacitive stage. The second stage may also be utilized as an unregulated output rail of the power supply. The invention is particularly suitable for power travelling wave tube amplifiers.