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在实验教学工作中,许多场合需要双电源。如果手边的电源是单电源,或者是双电源坏了一路,都希望将单电源变换成双电源来使用。下面介绍两种简易单变双电源电路,是我们在实验中以防电源突坏而作为备用的应急措施,使用效果很好。 图1电路采取了电阻串联分压形式实现电源单变双。电阻R_1,R_2是个耗能元件,作为双路相当内阻应尽量小,作为单路它是负载,阻值小了单路负载重,功耗大。所以,R_1,R_2只能在几百欧姆取值,功率选为3～10W之间。可见,图1电路只适用于功率较小场合。图1电路在R_1=R_2时,输出是正负对称电源;R_1≠R_2时,输出是不对称电源。
In experimental teaching, many occasions require dual power supplies. If the power supply at hand is a single power supply, or if the dual power supply is broken all the way, it is hoped that the single power supply can be used as a dual power supply. The following describes two kinds of simple single-variable dual power supply circuit, which is an emergency measure that we use as a backup in case of sudden power failure in the experiment. The use effect is very good. The circuit of Figure 1 adopts the series voltage divider of the resistor to realize the power supply single change pair. The resistors R_1 and R_2 are energy-consuming components. The internal resistance of two circuits should be as small as possible. As a single circuit, it is a load, and the resistance is small. The load of a single path is heavy and the power consumption is high. Therefore, R_1, R_2 can only be selected in hundreds of ohms and the power is selected between 3 and 10W. It can be seen that the circuit of Figure 1 is only suitable for low power applications. When the circuit in Figure 1 is at R_1=R_2, the output is a positive and negative symmetric power supply; when R_1≠R_2, the output is asymmetrical.