电阻式直流小电流标准恒流源

研制的电阻式直流小电流标准恒流源，用精密程控电压源和精密高值电阻器产生高准确度直流小电流的输出。利用电流电压负反馈自动调整，克服负载对输出电流的影响，实现直流小电流稳恒输出。在反馈支路加入滤波环节，大大降低了输出电流的噪声。在关键部位采用等电位屏蔽技术，克服湿度、泄漏和电磁干扰对输出电流的影响。该标准源量程范围10^-12A-10^-4A，在2pA量程准确度0．25％，输出电流噪声≤10fA，等效输出电阻10^16Ω。

DC Constant Low Current Standard Source Based on Resistance Model

DC low current source can produce high precisibn dc low currerit with precision programmable vohage source and high value resistor,and automati＇c adjust by use of current-voltage negative feedback technology, so it can eliminate the affects for output current,and realize outputting de low current constantly. In the feedback part, we used filter to reduce the noise. In the important part, we eliminated the affects of humidity, leak, electronic interference with equipotential screening technology~ The range of this standard source is：10^-12 A ～ 10^-4 A, the uncertainty in the 2 pA range is 0.25% , output current noise is below 10 fA,equivalent output resistance is 1016 Ω.