ELECTRIC CAMERA SHUTTER WITH RELATED CONTROLS
First Claim
1. In a camera having circuitry for automatically determining the extent to which film in the camera is exosed, said circuitry including electromagnetic means for terminating an exposure upon deenergizing of said electromagnetic means, a DC voltage source electrically connected to said electromagnetic means, and means for simultaneously supplying to said electromagnetic means a rippled direct current having a weak AC component so that the latter together with the supply from said DC voltage source counteract an electromagnetic attractive force generated due to magnetic hysteresis of said electromagnetic means when the latter is deenergized.
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Accused Products
Abstract
A camera having electrical circuitry for automatically determining the extent to which film in the camera is exposed. The circuitry includes an electromagnet for terminating an exposure upon deenergizing of the electromagnet. A DC voltage source is electrically connected to the electromagnet and there is also electrically connected thereto a supply of a rippled direct current having a weak AC component. This latter supply which takes place simultaneously with the supply from the DC voltage source counteracts an electromagnetic attractive force generated due to magnetic hysteresis of the electromagnet when the latter is deenergized.
3 Citations
3 Claims
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1. In a camera having circuitry for automatically determining the extent to which film in the camera is exosed, said circuitry including electromagnetic means for terminating an exposure upon deenergizing of said electromagnetic means, a DC voltage source electrically connected to said electromagnetic means, and means for simultaneously supplying to said electromagnetic means a rippled direct current having a weak AC component so that the latter together with the supply from said DC voltage source counteract an electromagnetic attractive force generated due to magnetic hysteresis of said electromagnetic means when the latter is deenergized.
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2. The combination of claim 1 and wherein said means for supplying said rippled current is a DC-DC converter.
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3. The combination of claim 2 and wherein a transistor is electrically connected to said electromagnetic means, a switching circuit means electrically connected to said transistor for controlling the latter to deenergize said electromagnetic means, and signal-transmission means electrically connected to said switching circuit means for transmitting to the latter exposure-determining signals for controlling said switching circuit means to terminate conductivity of said transistor to deenergize said electromagnetic means.
Specification