Abstract: An engraving device having a rotary system including a shaft supported in a bearing for rotation through very small angles, means to oscillate the shaft, an engraving needle carried on a lever attached to one end of the shaft adjacent the bearing and a dampening device characterized by the dampening device being arranged between the bearing and lever and the dampening device applying symmetrical forces on the shaft so that the dampening forces do not create bending forces on the shaft. Preferably the dampening device is located closely adjacent to the lever. A preferred embodiment of the dampening device uses a stationary support having a surface surrounding the shaft and either a closed ring of fluoro-plastic dampening material which is connected to the shaft and surface or two or more fluoro-plastic elements which are circumferentially spaced between the shaft and the surface and connected thereto.

Abstract: A circuit for digitally controlling the brightness of the electron beam of an electron beam deflection tube. The circuit permits switching at a very fast rate on the order of 200 nanoseconds. To this end, a differential amplifier is used having an input and an output transistor which may be of opposite conductivity type. The circuit may be protected from saturation state by a diode and from fluctuation in temperature by a further diode and a variable capacitor may be employed for effectively neutralizing the interelectrode capacitance of the electron beam tube.