| 摘要 |
<p>The coils is in a printed circuit and is tested by the resonance method. Each coil (S1-S4) is connected through a buffer amplifier (1-3) to a common wobbler (4). Coils not to be tested are short-circuited by diodes (5, 14-16) and a capacitor (6). The resonance voltage from the tested coil is rectified and applied to an adjustable operational amplifier (10). Its threshold, and thus the coil quality, is adjusted by a voltage source (11) connected to its second input. When a certain switching threshold is exceeded or not reached, a visual signal indicates a reject.</p> |
