| 摘要 |
The present invention relates to a circuit arrangement for a self-oscillating, transistorised and no-load-protected push-pull-type ultrasonic generator for generating ultrasonic oscillations with starting circuit by means of a resistor and diode, in which the feedback signal is obtained from the load current and which is operated with a pulsating direct voltage. It is the object of the invention to create a circuit arrangement for ultrasonic generators of the said type, the use of which results in considerable improvement in the efficiency of the ultrasonic generators. The object is achieved with the aid of a circuit arrangement in which the collector lines of the power transistors are coupled to a saturated current transformer and the no-load-protection of the ultrasonic generator is ensured by a series resistor in the positive feedline of the operating voltage, due to the fact that the ultrasonic generator is always under no-load voltage. This circuit arrangement results in an economic use of ultrasonic technology, mainly in the packaging industry, due to an operationally reliable, self-oscillating push-pull-type ultrasonic generator which is simple and thus inexpensive to produce.
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