数字万用表电路.doc

毕业设计说明书 数字万用表电路的设计 专业 电气工程及其自动化 学生姓名 班级 学号 指导教师 完成日期 年月日  数字万用表电路的设计 摘 要：数字万用表是采用数字化测量技术，把连续的模拟转换成不连续的、离散的数字并加以显示的仪表广泛用于电子及电工测量、工业自动化仪表、自动测试系统等智能化测量领域，显示出强大的生命力。本次设计的数字万用表将使用美国摩托罗拉公司生产的MC14433 A/D转换器，配合分流电阻、分压电阻、基准电阻可以测量交、直流电压，直流电流、电阻四位数码显示。在测量过程中使用量程开关来选择相应的电压、电流、电阻档位进行数据采集，之后将采集的信号V的直流电压值送到A/D转换器MC14433，转换为数字信号后由于操作过程中可能会有超量程现象，所以在设计中添加了超量程报警部分，当检测到超量程信号时， LED显示器闪烁，以示报警。精度高、抗干扰能力强，可扩展性强、集成方便。关键词：数字万用表；A/D转换器；MC14433； The Design of Digital Multimeter Abstract: Digital multimeter are using digital measurement techniques, the continuous analog signal to discontinuous, discrete digital signal and to display instrumentation, widely used in electronics and electrical measurement, industrial automation instruments, automatic test systems and other intelligent measurement, shows a strong vitality. The design of the digital multimeter will use the Motorola company produces the MC14433 A/D converter, cooperate to shunt resistance, dividing resistor, benchmark resistance can measure ac voltage ,dc voltage, dc current, resistance and the four digital display. In the measurement process using the scale setting switch to choose corresponding voltage, current, resistance gear in data collection, followed by the acquisition of the signal be converted to 0 to 2V DC voltage to the A / D converter MC14433, converted to A digital signal, the digital signal sent to lock to save-decoder, become BCD, again by LED display shows out. Among them, the range switching circuit controls the brightness of the corresponding decimal point so that the LED display shows a different range of readings. Operation may be over-range phenomenon, so add in the design of the alarm portion of the over-range, when the range signal is detected, the LED display flashes to show the alarm. The design of advanced digital display technology, high precision, strong anti-jamming capability, scalability, strong, easy integration. Key Words: Digital multimeter; A / D converter; MC14433; over range alarm