Electrical transmission or interconnection systems – Switching systems – Condition responsive
Patent
1988-07-18
1989-06-20
Miska, Vit W.
Electrical transmission or interconnection systems
Switching systems
Condition responsive
250206, 250214AL, 361175, H01H 3500, H01H 4724
Patent
active
048411647
ABSTRACT:
Light-sensitive switch structure for and method of turning a street light or other load on or off in response to variations in light level. The switch is designed to recognize a specific sequence of daily variations in light level and is capable of switching a load off at a light level lower than that at which the load is switched on. In a preferred embodiment, the switch consists of a photo-sensitive element, two operational amplifiers, a relay with its associated driver circuit, and a number of resistors forming voltage dividers. In accordance with the method of the invention, the photo-sensitive element, together with a resistor, establishes a signal voltage which varies in relation to the light level. Other resistors form voltage dividers which establish reference voltage levels at which desired switching is to occur. The operational amplifiers perform comparisons between the signal voltage and reference voltages and switch accordingly. One amplifier operates the relay which controls the load while the other biases the signal voltage to achieve the desired inverse operation. The stability of both amplifiers is insured by using feedback resistors to provide hysteresis, and a time delay circuit, consisting of a resistor and a capacitor to prevent sudden changes in the signal voltage. In other embodiments, two relays are used, one to control the load and the other to increase or decrease, by means of resistors, the currents through the operating coils of the relays to achieve the desired inverse off/on operation.
REFERENCES:
patent: 3351762 (1967-11-01), Adkins et al.
patent: 3529214 (1970-09-01), Corn
patent: 3629649 (1971-12-01), Del Zotto
patent: 3636357 (1972-01-01), Del Zotto
patent: 3916183 (1975-10-01), Duve et al.
patent: 4095100 (1978-06-01), Selick
LandOfFree
Light-sensitive switch structure and method with inverse off/on does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Light-sensitive switch structure and method with inverse off/on , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Light-sensitive switch structure and method with inverse off/on will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-527007