《简易半导体三极管参数测试仪的设计》-毕业论文.doc

PAGE 简易半导体三极管参数测试仪的设计 [摘要] 本测试电路能为小功率晶体管提供特定测试条件：VCE=10V，IB=10μA，并将此条件下的集电极电流IC经取样电阻转换为电压，辅以必要的运算电路将输出电压放大，以提高测量精度，该电压通过A/D转换芯片TLC549转换成数字量送入单片机进行数据处理，最后用LED数码管直接显示出晶体管的共射直流电流放大倍数?和交流电流放大倍数β?。此外，通过方波发生电路、分频电路、比例求和电路产生阶梯波，提供基极电流IB=0，10μA，20μA，30μA，通过积分电路产生0～10V的三角波用来给集电极提供扫描电压，最后用示波器显示出晶体管输出特性曲线。 [关键词] 晶体管；参数；测试仪；单片机；模数转换； The Design of Parameters Testing Circuit of the Semiconductor Transistor [Abstracts]: The design can provide particular condition for the transistor: VCE = 10V ,IB = 10μA ,and change IC which is in this condition into voltage by resistor. Amplifiering the voltage by the operational circuit in order to improve the accuracy of data processing. Output voltage can be changed from analog into digital data through the analog-digital conversion chip TLC549, and put the voltage into MCU to deal with. Finally and β will be displayed by LEDs.Step wave is generated by square wave generator , frequency dividing circuit, scaling circuit and summing circuit, in order to providing IB = 0,10μA, 20μA, 30μA..Triangular wave which range from 0～10V is generated by the integration circuit to provide the scanning voltage to the collector, finally the characteristic curve for output of transistor can be displayed by oscilloscope in X-Y mode. [Keywords]: Transistor; Parameter; Testing circuit; MCU; Analog-to-digital conversion 目录 TOC \o 1-3 \h \z \u HYPERLINK \l _Toc232561258 1引言 5 HYPERLINK \l _Toc232561259 2 任务分析及方案确定 5 HYPERLINK \l _Toc232561260 2.1 设计要求 5 HYPERLINK \l _Toc232561261 2.2 设计方案 5 HYPERLINK \l _Toc232561262 2.2.1 测试电路方案论证 5 HYPERLINK \l _Toc232561263 2.2.2 采样电路方案论证 6 HYPERLINK \l _Toc232561264 2.2.3 显示部分方案论证 6 HYPERLINK \l _Toc232561266 2.3 系统整体框图 6 HYPERLINK \l _Toc232561271 3 理论分析与参数计算 7 HYPERLINK \l _Toc232561272 3.1 共发射极直流电流放大系数 7 HYPERLINK \l _Toc232561274 3.2 共发射极交流电流放大系数b 8 HYPERLINK \l _Toc232561275 3.3 采样电路 8 HYPERLINK \l _Toc232561276 3.4 A/D转换 9 HYPERLINK \l _Toc232561286 3.5 数据处理部分 9 HYPERLINK \l _Toc232561289 3.6 放大电路