Model JO415 DC microammeter is suitable for students to measure weak current and slimelectric potenial in laboratory of middle school and polytechnic school.

JO415型直流安培计适用于中学、中专等学校，可微弱电势用。

For electrical properties of MOS capacitors, the C-V curves were obtained by LCR meter (HP4284A), and picoampere meter (HP4140B) was used to measure the J-V curves.

另外电电容电阻计仪(HP4284A)进行C-V曲线；微安培计仪(HP4140B)进行J-V曲线。

The main structure have:Electromagnet and Heng galvanism source, numerical type Gauss account(the effect of Huo Er) and ammeter and volt account, have control dish of illuminate the system.

电磁铁和恒流电源、数字式高斯计 （霍尔效应）、安培计和伏特计、配有照明系统的控制盘。