（1）输出电压：范围0～＋9.9V，步进0.1V，纹波不大于10mV； （2）输出电流：500mA；　
（3）输出电压值由数码管显示；　（4）由“＋”、“－”两键分别控制输出电压步进增减；　
（5）为实现上述几部件工作，自制一稳压直流电源，输出±15V，＋5V。 2．发挥部分　
（1）可通过一个扫描式矩阵键盘对输出电压进行预置在0～9.9V之间的任意一个值；　（2）用按键可进行加减电压值，实现输出电压变化（步进0.1V不变）；　（3）扩展输出电压种类（比如三角波，方波）。
附件包含程序和pcb((1) output voltage: range 0 ~ +9.9 V, step 0.1 V, ripple no greater than 10mV;(2) output current: 500mA;
(3) the output voltage value is displayed by the digital tube;(4) the output voltage step is decreased by "+" and "-".
(5) in order to realize the above work, a stable dc power supply is made, and the output is plus or minus 15V.2.Play part
(1) the output voltage can be preset at any value between 0 and 9.9V by a scanning matrix keyboard;(2) the voltage value can be added by pressing the key to realize the output voltage change (step 0.1V invariant);(3) extend the output voltage type (such as triangular wave, square wave).)