| 摘要 |
<p>The reading of information stored in the form of small magnetic elements on a plate, is achieved using an inductive reading head. The card (3) contains a matrix of small metallic elements (15) used to store data. As the card is inserted into the reader two rows of reading coils are passed. Each reading cell consists of a transmission coil (6) supplied from an A.C. generator. A receiver coil (7) is located parallel to a reference coil (8) and with no cell present the signal outputs are identical. A bridge is used to compare the signals. The presence of a cell causes the receiver coil output to fall and the reference coil signal to increase.</p> |
