| 摘要 |
A switch signal input apparatus using an alternating current power source is disclosed. According to an embodiment of the present invention, one terminal of a switch is connected to a photocoupler, and the other terminal is commonly connected to an alternating current (AC) power source. When a user turns on a switch, a switch signal is generated by using the AC power source. Therefore, only one interconnection line and an input pin are required for one switch. Thus, the number of interconnections is reduced, and an installation process is simplified compared to a prior art, where a microcontroller unit (MCU) and an input circuit generate the switch signal, output the signal to one terminal of the switch, and directly receive the switch signal through the other terminal of the switch. Also, according to a preferred embodiment of the present invention, one terminal of the switch is not directly connected to the MCU and the input circuit, but rather via the photocoupler, such that AC power is not directly connected to the MCU and the input circuit, even when the AC power is connected to a switch connecting pin due to an erroneous interconnection, thereby protecting the MCU, or the likes from the erroneous interconnection. |
