| 摘要 |
By indicating the remaining lighting time in traffic signal lamps for drivers the overspeed and accidents of vehicles can be prevented from happening. The oscillation circuit (4) which is composed of resistances (R2,R3), crystal oscillator, inverter circuit (INV1) and integrated circuits (IC3, IC4, IC5) is connected to the source (3). The memory circuit (5) which is composed of a D-type flip flop, a decade counter and an up/down counter is connected to the oscillation circuit through AND gates and a buffer circuit.
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