Patent US 6,095,092

An animal control device, and method for confining an animal within a boundary identified by a current carrying conductor. The animal is equipped with a control device, as an antenna coil, which is coupled to a magnetic flux emanating from the conductor. When the animal approaches the boundary conductor, the change in voltage across the antenna coil is compared with a reference change in voltage. As the distance closes from a charging animal, the rate of change in voltage from the antenna coil increases correspondingly, providing a reliable detection of the animal's imminent crossing of the boundary. Conventional animal correction circuitry is provided which, in response to a detected voltage change, issues a corrective stimulus to the animal to stop the animal from crossing the boundary.