| 摘要 |
<p>A loop-powered, backlit liquid crystal display (LCD) device (10) responds to a current instrumentation loop for providing a current representative of the value to be measured and has an LCD (24) for displaying the measured value which is backlit by one or more light-emitting diodes (D1,D2). The LED circuit (18) is driven by the current of the current instrumentation loop for backlighting the LCD. A current regulating amplifier (Q1) controls the brightness of the LED (D1) and a voltage inverter (34) for driving the LED without increasing the burden on the instrumentation loop.</p> |
