Abstract: A three-way or four-way switching circuit for lighting, and the like, is described. One three-way switch is replaced with an electronic switch. Both legs of the switching circuit are powered all the time and current is sensed in the legs to determine when one of the three-way or four-way switches has been switched. This information is used to turn the light on and off.

Abstract: A three-way or four-way switching circuit for lighting, and the like, is described. One three-way switch is replaced with an electronic switch. Both legs of the switching circuit are powered all the time and current is sensed in the legs to determine when one of the three-way or four-way switches has been switched. This information is used to turn the light on and off.

Abstract: A three-way or four-way switching circuit for lighting, and the like, is described. One three-way switch is replaced with an electronic switch. Both legs of the switching circuit are powered all the time and current is sensed in the legs to determine when one of the three-way or four-way switches has been switched. This information is used to turn the light on and off.

Abstract: A three-way or four-way switching circuit for lighting, and the like, is described. One three-way switch is replaced with an electronic switch. Both legs of the switching circuit are powered all the time and current is sensed in the legs to determine when one of the three-way or four-way switches has been switched. This information is used to turn the light on and off.

Abstract: Each hydrophone receiver element is attached in electrical parallel with the series combination of a switching diode and a zener diode so that the physical orientation of the element is the same for each element network. The response element networks then are assembled into a cable section, the element networks constituting a group array. A test circuit applies a relatively high dc voltage input to the cable section. The switching diodes are not rendered conductive for the elements properly connected. Hence, the output is substantially the same as the input. However, if one or more of the elements are reverse connected, the switching diode for that response element is rendered conductive and the output drops to the level of the zener breakdown voltage. Hence, the whole array-connected group can be tested with a single test.