摘要：数控直流稳压电源就是能用数字来控制电源输出电压的大小，而且是能使输出的直流电压保持稳定、精确的直流电压源。本文采用AT89C51单片机与桥式整流电路及三端集成稳压器实现对直流稳压电源的数字化控制。电路由数字控制部分、D／A转换部分、可调稳压部分组成。通过改变输入数字量来改变输出电压值(A／D转换后电压值)，经集成运放放大和射极输出器输出，间接地改变输出电压的大小。数字控制部分采用+，-按键来调整控制电压值，二进制计数器输出输入到D／A转换器中，经过D／A转换后，控制调整步进为0.1V，经测试，可输出0～12V的稳定直流电源，输出电压采用LED共阴极数码显示。该系统具有通用性好、可靠性高、线路简单、成本低廉、使用方便的优点。

关键词：AT89C51；转换；数控；电压源；桥式整流

Abstract:Numerical-controlled dc voltage source is the source that can control the output voltage, make the output voltage remain stable and precise. We can use AT89C51 microcontroller, bridge rectifier circuit and three integrated stabilizer to realize the digital control of dc voltage. Electric circuit is made up by digital control circuits, D/A transformation and adjustable voltage. Output voltage can be changed by input digital quantity (voltage value after A/D conversion). The output voltage can be indirectly changed by the integrated operational and output shot. Digital control adopts buttons +,- to adjust and control voltage value. Binary counter output and input value to D/A converter. Set the step of adjustment with 0.1V after D/A transformation. By test, it can supply stable dc power of 0 ~ 12 V. The output voltage of cathode displays by LED digital. The system has a series of advantages, such as excellent versatility,high reliabilitysimple line,low cost,and easy to use.

Keywords: AT89C51;Transformation; Numerical control; Voltage source; Bridge rectifier