| 摘要 |
Apparatus for determining the number of turns of a test coil wound on a magnetic core comprising a reference coil with a pre-fixed number of turns wound on a reference core and coupled to a resistive load. The test coil is linked to the reference coil by a single-turn primary supplied with a-c current of substantially constant amplitude. An adjustable resistive load is connected across the test coil. Both load resistors are of low ohmic value, to operate the two coils as heavily-burdened current transformers. The coil voltages are compared by a phase-sensed comparator, and the adjustable resistor is set to produce a null comparison condition. At this condition, the number of turns of the test coil will be proportional to the resistance of the adjustable resistor, and this number is indicated by a calibrated digital read-out device.
|
