| 摘要 |
The invention provides a current detecting device such that it is possible to detect a wide range of current using one magnetic core, and possible, when an overcurrent flows, to reliably detect the overcurrent. The invention includes an exciting coil (3) wound around a magnetic core (2) enclosing a conductor through which flows a measurement current, and an oscillator circuit (4) that generates a square wave voltage that causes the magnetism of an exciting current supplied to the exciting coil (3) to invert in accordance with a set threshold value, with the magnetic core (2) in a saturated state or a state in the vicinity thereof. Furthermore, the invention includes a duty detector circuit (5) that detects the measurement current based on variation in the duty of the square wave voltage output from the oscillator circuit (4), a frequency detector circuit (7) that detects an overcurrent of the measurement current based on the frequency of the square wave voltage output from the oscillator circuit (4), and an oscillation amplitude detector circuit (6) that detects an overcurrent of the measurement current based on the wave height value of the square wave voltage output from the oscillator circuit (4). |
