在微机接口或某些仪表系统中,有时需要一组稳定的负极性电源(如AD-DA 和运算放大器等),而在单板机或单片机系统中又往往不具备负电源功能,在一些系统微机中虽然有负电源,但由于某种原因又不允许或不希望负电源与+5V 电源共地。因此,在用到负 In the computer interface or some instrumentation systems, sometimes require a stable set of negative polarity power (such as AD-DA and operational amplifiers, etc.), and in the single-chip or microcontroller system often do not have the negative power function, in some systems Although the computer has a negative power supply, but for some reason they do not allow or do not want to negative power and + 5V power supply ground. Therefore, the negative is used