论文部分内容阅读
在很多有关物理学的部门中,如电离真空测量、光电流、X射线、核物理等,都必须测量非常微弱的电流.微电流的范围大概从1微安起始,一直到10~(_18)安.我们知道1安培电流相当于每秒通过6×10~(18)个电子,因此微也流的最小测量范围,希望到达每秒钟通过几个电子.一般10微安满刻度的电流表,可以用来测量1微安的电流.更小的电流,就要用反射光检流计来测量.由于空气中的分子撞击检流计线圈,即所谓布郎Browuian运动,以及在电路中电阻所产生的热噪声,往往使检流计的镜子经常移动.在一般室温下,这些噪声可以达到相当于10~(12)安的输入电流,因而使反射
In many physics-related departments, such as ionization vacuum measurements, photocurrents, X-rays, nuclear physics, etc., very weak currents have to be measured.The range of micro-currents starts at about 1 microampere up to 10 ~ (_18 ) Ann. We know that 1 amp current is equivalent to passing 6 x 10 ~ (18) electrons per second, so the microstrip also flows in the minimum measuring range, hoping to reach several electrons per second. A typical 10 microamps full scale ammeter , Can be used to measure the current of 1 microamp.More small current, it is necessary to use a reflective galvanometer to measure.Because the molecules in the air impact galvanometer coil, the so-called Brown Browuian movement, as well as in the circuit resistance The thermal noise that is generated tends to move the galvanometer mirrors frequently and, at normal room temperature, these noises can reach an input current equivalent to 10 to 12 Amps, causing the reflection