主控电路包含了12位的数模转换芯片tlc5618和10位的模数转换芯片tlc1549对恒压和恒流模块电路进行采样经过AT89S52单片机可实现恒压模式下设计2-15V范围的设定和0.01v的步进；恒流模式下实现0.1-2A的范围设定和0.01A的步进。恒压和恒流模块电路采用OP07运放（或UA741）、康铜丝电阻和开关管IRF540组成恒压及恒流的负载电路。继电器电路可实现工作模式的切换。-Control circuit includes a 12-bit digital-analog conversion chip tlc5618 and 10-bit analog to digital conversion chip tlc1549 of Constant voltage and current sampling circuit module can be achieved through the constant pressure mode AT89S52 microcontroller to design 2-15V range of settings and 0.01v step　constant current mode to achieve the range of 0.1-2A step setup and 0.01A. Constant voltage and constant current circuit using OP07 op amp modules (or UA741), Hong copper resistance and switch IRF540 constant pressure and constant composition of the load circuit. Relay circuit switching mode can be realized.