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I was just trying to simulate a simple transistor circuit as common emitter in Proteus 8. However the I observe that the base-emitter voltage (Vbe) of the transistor 2N2222 is showing as 1.36v instead of 0.7v. This is a huge difference. Is there anything wrong with the attached circuit? Also Vce is 2.82v and I am not sure whether it is in saturation or not.

enter image description here

Below the the text script of the transistor model.

{*DEVICE} NAME=2N2222 PREFIX=Q {*PROPDEFS} MODEL=LISA Model,STRING PACKAGE=PCB Package,PACKAGE,0 PRIMITIVE=Primitive Type,HIDDEN STRING {*INDEX} {CAT=Transistors} {SUBCAT=Bipolar} {DESC=Silicon NPN Low Power High Frequency Bipolar Transistor (500mW, 200ºC)} {*COMPONENT} {PRIMITIVE=ANALOGUE,NPN} {MODEL=LX_NPN_SSHF,BIPOLAR} {PACKAGE=TO18}

UPDATE:

I tried using different transistors and found that this behavior occurs for transistors of LISA model. It is found working fine for transistors of SPICE model e.g. 2N222A, PN2222, BC548C etc. But still why LISA model does not give 0.7v for Vbe?

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No, something is quite wrong with the model or simulator. You'd normally expect 600-800mV at the base under those conditions. 1.36V is way too high. Your circuit looks fine. Maybe try a different transistor.

I'd also expect the transistor to be saturated so Vce should be much less than 1V.

You can also try LTspice, a free download.

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  • \$\begingroup\$ Agreed. I'd add about \$80\:\text{mV}\$ to the estimate because the Ohmic base resistance and the base current (BJT is saturated.) But that 2N2222 model is off by quite a bit, anyway. \$\endgroup\$ – jonk Apr 20 at 9:57

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