Abstract: In a hydraulic control system of an automatic power transmission for an automotive vehicle, the frictional units in the transmission mechanism are operated by a line pressure which is regulated to vary with torque output of the engine and which is reduced to be variable with energy output of the engine when one frictional unit is to be actuated to make an upshift between predetermined forward drive gear ratios or reduced to a substantially constant when another frictional unit is to be actuated to make a downshift between other predetermined forward drive gear ratios for thereby reducing or eliminating shocks which would otherwise be created during the upshift or downshift.

Abstract: Disclosed is a brightness control device for use with fiber optical lamps, comprising a diaphragm which is arranged unilaterally in the light beam between the lamp light source and the light entrance area of the fiber optical conductor. The diaphragm comprises a variable size diaphragm which is designed such that the cross-section of the light entrance area of the fiber optical conductor is asymmetrically and unilaterally reduced in order to maintain a constant lamp color temperature and emission characteristic.