| 摘要 |
An electric fence sensor system has a low power detection mode. When the presence of a body near the fence is detected, the system will switch from the sensing mode to electrified mode for a preset time interval. During this time a high voltage pulse will be present, before the system resumes the detection mode. The power and/or frequency may be dependent on the size of the perceived object. The system may comprise an energizer 2, a wire 3 and a sensing device 1. The sensing device may use a change in capacitance to detect the presence of a body. An LC or RC oscillator may be used where the wire to be electrified forms part of the capacitance of the circuit. Microprocessor a measures the frequency of the oscillator-wire circuit several times a second, where changes in the frequency are caused by small changes in the capacitance arising from the presence of a person or animal. The microprocessor uses an algorithm to decide whether to switch into the electrified state. A single wire may be used for both detection and electrification, alternatively separate wires may be used. |
