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一、电源极性自动识别电路 在电子装置中,常常要用直流电源供电,且电源的极性必须按要求连接,若因疏忽接反了电源的极性,就会损坏电路中的元件。本文介绍一种电路(见图1),无论你在接线时怎样连接(正极接C或接D),二极管桥式 电路均能自动识别电源的极性,使输出电压极性始终保持不变。 例如当C端接电源正极,d端接电源负极时,二极管D_1和D_3,导通,D_2和D_4截止,负载上可获得正的直流电压;若C端接电源的负极,d端接电源的正极,则D_2和D_4导通,D_1和D_3截止,负载上仍可获得正的直流电压。可见由于二极管桥式电路的作用,输入电源的极性可任意连接。
First, the automatic identification of power polarity circuit In electronic devices, often use DC power supply, and the polarity of the power must be connected as required, if neglected reverse the polarity of the power supply, it will damage the circuit components. This article describes a circuit (see Figure 1). The diode bridge circuit automatically recognizes the polarity of the power supply, keeping the polarity of the output voltage constant, no matter how you connect it during wiring (positive or negative). For example, when C is connected to the positive terminal of the power supply and d is connected to the negative terminal of the power supply, the diodes D_1 and D_3 are turned on, and D_2 and D_4 are turned off. A positive DC voltage can be obtained from the load; if C is connected to the negative terminal of the power supply, Positive, then D_2 and D_4 conduction, D_1 and D_3 cut-off, the load can still get a positive DC voltage. Visible due to the role of diode bridge circuit, the polarity of the input power can be arbitrarily connected.