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AD\Test\2026\September\MeasureDiodeReverseILMC662.SchDoc

01【二极管反向电流】

一、测量电路

前几天测量了这款LMC662低输入偏置电流运放的性能， 通过合适的输入端口保护环可以使得漏电流降低到几个到十几个飞安。 下面我们利用这个运放来测量一下， 普通的晶体管三极管它的基极的漏电流以及基极的电位的情况， 也就是在基极悬浮状态下， 三极管的基极究竟电压是多少？ 我们先通过这个电路测量一下， 三极管BE反向导通电流是多少？ 现在选择的三极管是nPn硅3极管，型号为8050。 通过电容充电方法来测量一下它的反向漏电流，

我们铺设单面PCB， 通过一分钟制板方法获得测试电路板， 一分钟之后，得到测试电路板， 焊接电路板，并通过高压水蒸气以及除胶剂， 对电路板表表面进行彻底的清洗， 清洗之后还使用热风枪对表面进行烘干。

二、测量结果

所选择三极管的电流放大倍数为285。 首先我们测试一下三极管BE之间的反向电流， 施加的反应电压为2.55伏， 通过0.1微法上面充电电压的变化率， 可以计算出对应的B一端电流为36.1P安， 再测量一次。 对应的BE反向电流为31.4P安，

下面我们测量 CE反向电流， 反应电压依然是2.55伏， 不过这一次它对应的电流变化并不是单调的， 下面我重新再测量一次对应的电容电压变化， 可以看到它对应的电压是下降， 意味着电流是-53.9P安， 这个负电流有可能是 LMC.662对应的输入电流引起的， 重新再测量一下 BE之间的反向电流， 大小为35.3PA， 与前面测量的结果是相符合的， 说明此时整个电路测量电流的功能是正常的， 接下来测量不加三极管对应的电流， 对应的是-366飞安， 这有可能是电路不稳定引起的， 再测量一次，这次得到结果是-205非安， 这反映了 lMc 622本身正输入流入的电流大小。 接下来再测试一次， 此时对应的是负-155飞安， 重新再测试一次， 对应的是-143费安， 这个电流大小应该对应的是LMC662正输入端对应的输入电流，也就是没有施加。 三极管CE反向偏置时对应的基础电流。

接下来将三极管CE反向偏置放置在电路中。 测量出来的电流为23.9飞安。 再测量一次， 对应的是负39飞安， 再测量一次，对应的是-64.1飞安， 再测量一次， 此时电压变化比较稳定， 对应的是负66.7飞安。 在等待一段时间以后， 对应的电流变化到36.9飞安， 最后我们可以看到对应的电流越来越小， 由此有可能说明c1之间的反向偏电流与lMC662正输端的输入电流达到一致。 由此我们也可以大体知道， 三极管C1之间的反向偏置电流大概在200飞左右。

tdim=[0.0000,1.3186,2.5038,3.7336,4.9453,6.1547,7.3640,8.5524,9.7824,10.9912,12.2005,13.4148,14.6202,15.8296,17.0398,18.2202,19.4578,20.6682,21.8790,23.0876,24.2656,25.5041,26.7138,27.9248,29.1347,30.3421,31.5649,32.7626,33.9513,35.1857,36.3899,37.6012,38.8072,39.9885,41.2270,42.4470,43.6467,44.8570,46.0687,47.2739,48.4831,49.6710,50.9057,52.1160,53.3213,54.5315,55.7093,56.9487,58.1635,59.3723,60.5812,61.7875,62.9968,64.2096,65.3868,66.6237,67.8446,69.0423,70.2548,71.4365,72.6710,73.8833,75.0612,76.2996,77.5101,78.7183,79.9277,81.1083,82.3470,83.5550,84.7650,85.9761,87.1534,88.3963,89.6039,90.7912,92.0199,93.2335,94.4424,95.6526,96.8311,98.0701,99.2794,100.4899,101.6957,102.9062,104.1150,105.3265,106.5056,107.7437,108.9532,110.1639,111.3715,112.5597,113.7911,115.0011,116.1850,117.4212,118.6294,119.8396]vdim=[0.0043,0.0048,0.0052,0.0056,0.0061,0.0065,0.0070,0.0074,0.0079,0.0083,0.0087,0.0092,0.0096,0.0101,0.0105,0.0109,0.0114,0.0118,0.0123,0.0127,0.0132,0.0136,0.0140,0.0145,0.0149,0.0154,0.0158,0.0162,0.0167,0.0171,0.0176,0.0180,0.0184,0.0189,0.0193,0.0198,0.0202,0.0206,0.0211,0.0215,0.0220,0.0224,0.0228,0.0233,0.0237,0.0241,0.0246,0.0250,0.0255,0.0259,0.0263,0.0268,0.0272,0.0276,0.0281,0.0285,0.0289,0.0294,0.0298,0.0303,0.0307,0.0311,0.0316,0.0320,0.0324,0.0329,0.0333,0.0337,0.0342,0.0346,0.0350,0.0355,0.0359,0.0363,0.0368,0.0372,0.0376,0.0381,0.0385,0.0389,0.0394,0.0398,0.0402,0.0407,0.0411,0.0415,0.0420,0.0424,0.0428,0.0433,0.0437,0.0441,0.0445,0.0450,0.0454,0.0458,0.0463,0.0467,0.0471,0.0476]

#!/usr/local/bin/python# -*- coding: gbk -*-#============================================================# TEST1.PY -- by Dr. ZhuoQing 2026-09-26## Note:#============================================================fromheadmimport*fromtsmodule.tsvisaimport*dm3068open()tdim=[]vdim=[]C=0.1e-6starttime=time.time()foriinrange(100):t=time.time()-starttime tdim.append(t)v=dm3068vdc()vdim.append(v)time.sleep(1)tspsave("measure",tdim=tdim,vdim=vdim)printff(i,t,v)dv=vdim[-1]-vdim[0]dt=tdim[-1]-tdim[0]Ioffset=dv*C/dt printff(dv,dt,Ioffset)plt.plot(tdim,vdim,lw=3)plt.xlabel("Time(s)",color="steelblue",fontsize=24)plt.ylabel("Vout(V)",color="steelblue",fontsize=24)plt.grid(True,which='both',linestyle='--',alpha=0.7)plt.tight_layout()plt.show()#------------------------------------------------------------# END OF FILE : TEST1.PY#============================================================

根据前面测试的结果，可以看到BE结反向偏置电流大体在35P安左右。 ，测量结果还是相对比较稳定，毕竟它的电流比较大 ，通过这种电容充电方法，可以比较稳定的获得BE节反向电流大小 。如果将这个电流除以三极管的电流放大倍数 ，可以得到123飞安 ，很有趣的是，这个电流与 CB结之间的反偏电流大体相当，但是我们知道从理论上 BE节和CE结，它们各自反向偏电流与三极管的放大电流放大倍数并没有直接关系。

接下来我们再测量三极管， 在基极开路情况下，CE之间透电流穿流， 穿透电流大小为36.1P安。 反过来我们测量在积极开路情况下EC之间的穿透电流， 我们将反应偏置电压提高到5伏。 这一次测量得到的EC之间的反向串联电流大约为2109P安。

接下来我们将be之间短路，然后再测量CE之间的漏电流，查看一下这个电流与CB和Be两个PN结反向漏电流之间的关系。 ，根据电容充电测量结果显示，这个电流大小大体上为20.8pA。

接下来我们再重新测试一下， 也就是等系统稳定之后 测量数据显示，漏电流已经减少到1.77P安了， 再测量一次， 电流下降到1.08P安， 重新再测量一次， 漏电流为1.11P安， 现在应该是稳定了， 接下来我们将B悬空。 得到的CE之间的穿透电流为4.76P安， 这比刚才测量的36.1pA要小得多。 ，这也反映了三极管的这种漏电流其实是相当不稳定的， 也可能说明我们这样测量的手段本身也并不十分精确。

#!/usr/local/bin/python# -*- coding: gbk -*-#============================================================# TEST1.PY -- by Dr. ZhuoQing 2026-09-26## Note:#============================================================fromheadmimport*fromtsmodule.tsvisaimport*dm3068open()#------------------------------------------------------------tdim=[]vdim=[]C=0.1e-6starttime=time.time()foriinrange(100):t=time.time()-starttime tdim.append(t)v=dm3068vdc()vdim.append(v)time.sleep(1)tspsave("measure",tdim=tdim,vdim=vdim)printff(i,t,v)dv=vdim[-1]-vdim[0]dt=tdim[-1]-tdim[0]Ioffset=dv*C/dt printff(dv,dt,Ioffset)plt.plot(tdim,vdim,lw=3)plt.xlabel("Time(s)",color="steelblue",fontsize=24)plt.ylabel("Vout(V)",color="steelblue",fontsize=24)plt.xticks(fontsize=16)plt.yticks(fontsize=16)plt.grid(True,which='both',linestyle='--',alpha=0.7)plt.tight_layout()plt.show()#------------------------------------------------------------# END OF FILE : TEST1.PY#============================================================

※总结 ※

本文使用了IMC662运放， 测量了一个8050三极管对应的反向漏电流的大小。 对于be之间的反向漏电流， 测量结果显示在大约在35P左右。 对于CB之间的反压穿传输电流， 在150飞安左右，因为这个电流很小， 使用电路板测量的结果并不稳定。