| 摘要 |
PURPOSE:To reduce power consumption by lighting an operating display light from a pulse signal from an oscillating circuit of a projecting circuit dynamically. CONSTITUTION:A light emitting element 3 is lighted synchronously with a pulse signal A from the oscillation circuit 1 of the projection circuit 4. When the photodetector 5 is not lighted, the output B of the photodetection circuit 6 goes to 'L' and the output C of the AND gate 12 is at 'L' and the display light 9 is not lighted. When the detector 5 receives a light, the output C of the gate 12 goes to 'H' synchronously with the pulse signal of the oscillating circuit 1 and the transistor 11 is turned on intermittently and the operating display light 9 is lighted dynamically. Through the constitution above, the power consumption is reduced without complicating the circuit.
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