摘要
电阻热噪声测量需要隔离环境噪声对测量的干扰。通过远程控制扫频噪声测量发现教学实验室即使在无人时仍有明显特征的环境噪声;另一方面,位于电阻旁边的热电偶即使在非测量状态下也会引入噪声。为此,高屏蔽能力的变温样品盒成为变温测量电阻热噪声的关键。本文研制一款用于实验教学的样品盒,测温热电偶设置在样品盒外,但与电阻保持良好热接触;进一步结合锁相放大器A-B共模输入和输入带宽修正,获得较好的实验效果。
Resistance thermal noise measurement needs to shield the environmental noise interference from the measurement.Through remote measurement of noise with a frequency sweep mode,it is found that there was obvious characteristics of environmental noise higher in strength than the thermal noise in the teaching laboratory even nobody was there.On the other hand,the thermal couples local near the resistor to measure its temperature can introduce environmental noise to the measurement even it was in the shutdown state.Therefore,a sample box with capacities of high noise-shielding and temperature-measurement of the resistor at the same time becomes the key to the resistance thermal noise measurement at variable temperatures.Combined with the A-B common mode input of a lock-in amplifier and the input bandwidth correction,a sample box with the thermal couple outside the shielding box but with good thermal contact with the resistor is developed for teaching experiment,which produces desired result.
作者
申玉宽
何振辉
SHEN Yukuan;HE Zhenhui(School of Physics and Astronomy,Sun Yat-Sen University,Zhuhai 519082,China)
出处
《大学物理实验》
2023年第2期54-58,共5页
Physical Experiment of College
基金
2022高等学校教学研究项目(DWJZW202238zn)。
关键词
热噪声
环境噪声
屏蔽
锁相放大器
变温测量
实验教学
thermal noise
environmental noise
shielding
lock-in amplifier
measurement in varying temperature
experimental teaching
