| 摘要 |
A sensing device comprised of a sensing circuit which changes its operating characteristics when an object comes near it. The sensing circuit produces a change in output voltage proportional to the change in relative distance between the sensing circuit and an object. The actual output voltage is a function of both target distance and control circuit input voltage. The control circuit includes a comparator for comparing the steady state output voltage to a reference voltage and adjustment system for adjusting the input voltage to change the steady state output voltage such that the steady state output voltage approximately equals the reference voltage. The control circuit reacts only to reductions in the steady state output voltage, indicative of mechanical wear, and not to increases in output voltage, indicative of currency thickness measurement. |
