| 摘要 |
A low error, plugged test lead detecting circuit for providing accurate current measurement and the method using the same. When a test lead of the plugged detecting circuit is plugged into a split contact jack of the plugged detecting circuit, the circuit stops oscillating during operations for a test lead detecting mode or a fuse open detecting mode. During the test lead detecting mode, if the test lead is plugged into the split contact jack, the oscillating unit stops automatically and outputs a quiescent state. Conversely, if the test lead is unplugged into the split contact jack, the oscillating unit generates a pre-determined frequency pulse according to the oscillating unit. During the fuse open detecting mode, the test lead is plugged into the split contact jack. If a fuse is presented, the oscillating unit stops automatically and outputs a quiescent state. If the fuse is not presented or blown, the oscillating unit generates a pre-determined frequency pulse according to the oscillating unit. During the current measurement mode, the protecting unit and the shunt form a series parallel circuit when the test lead is plugged into the split contact jack. The impedance of the shunt is negligible in comparison to the impedance of the protecting unit, and the voltage drop across the shunt is proportional to the injected current.
|
