Abstract: A non-destructive process for estimating the ageing of an article made of a composite material is described comprising a preliminary phase in which at least one chart is prepared characterizing the change in the attenuation of ultrasonic waves in the composite material as a function of weight loss thereof, and a checking phase in which the attenuation of ultrasonic waves in the article made of the composite material is measured and the weight loss of the article is determined using the chart prepared in the preliminary phase, the weight loss being representative of the ageing of the article.

Abstract: A line deflection circuit for a television receiver or a switched-mode power supply operate with a switching transistor that is connected in series with the primary winding of a transformer and is periodically switched on and off by a switching voltage. In such a circuit, appreciable turn-on and turn-off losses, which reduce the overall efficiency of the circuit, are produced at the switching transistor, particularly at higher operating frequencies. Within a control circuit a DC voltage source is connected to the base of the switching transistor via a periodically actuated switch element and a coil having a core and a tap. The two parts of the coil are wound in opposite senses, and the tap is connected via a diode to ground or to the emitter of the switching transistor.