| 摘要 |
<p>A potentiometer comprises a resistive first track (1) with first and second terminals (2, 3) to which a voltage is applied. A conductive wiper (5) traverses the first track and is connected to a third terminal (7) to provide an analogue output signal dependent on the position of the wiper. A conductive second track (8) has discrete insulating regions (9) along its length and is provided with a fourth terminal (10). The wiper (5) also traverses this second track (8). It is arranged that sharply defined transitions in electrical output (logic transitions) occur at the fourth terminal (10) as the wiper (5) traverses boundaries between the insulating regions (9) and the second track (8). The analogue output from the third terminal (7) at positions of the wiper (5) where the output transitions at the fourth terminal (10) occur, provide calibration points to permit accurate relating of the wiper position to the output from the third terminal (7) at any location between the calibration points. Particularly applicable to position sensing, e.g. in engine management systems.</p> |
