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Dear friend
your reply is right. By setting ikf=0, rb=0 and vin=1mv, then
gm = IC/Vt = 410.8/25.8=15.9
ic = gm*vbe = 15.9*0.001=15.9mA and by calculating from graph ic=(424mA-397mA)/2=13.5mA
But now one question is remained, I have never seen IKF in data sheets. How can measure or calculate...
There is no real transistor and everything is in simulator. Its bias is correct since it is in power amplifier mode. Problem is that in simulation nothing works correctly (in real world I don't know what will happen). Smoking is not my consideration here and also simulator can check for it but...
Dear friend
I used 2n2222 transistor not 2n3904 and maximum current of 2n2222 is about 800mA and here it passes about 400mA and Vce>2 so it is not in saturation region. Also I know that single resistor bias is not good, but here it is not the case. My question is although the transisto is not...
I think the source of problem is here but I don't know why?
We know that Ic = Is*exp(Vbe/Vt) but by this equation Ic = 14.34e-15 * exp(0.878/0258) = 3.5A which to far from reality.
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In PSpice when I right click on 2n2222 and select "edit PSpice model" it shows 2 models and I think it uses second one:
1.
.model Q2N2222A NPN(Is=14.34f Xti=3 Eg=1.11 Vaf=74.03 Bf=255.9 Ne=1.307
+ Ise=14.34f Ikf=.2847 Xtb=1.5 Br=6.092 Nc=2 Isc=0 Ikr=0 Rc=1
+ Cjc=7.306p Mjc=.3416 Vjc=.75 Fc=.5...
In model which I used RE=0.1. I convert it to RE=0 and relaunch the simulation as you said it should be near ideal model but the new Ic swing is about 80mA not 160mA.
First. would you explain more detail about how parasitic resistance of emitter affect the current flow in collector (voltages trivial)
Second. As you said above it is about 10% but in my simulation it it about 75%.
Third. As PSpice ref. manual page 209 "Bipolar transistor equations for DC...
I need to analyze power amplifier so current is rather high, but you said it is near saturation region, plz tell me why? and also I repeat this design and simulation with 2n3904,( other items were intact, therefore Ic = 290mA and vce>4 volt ) and the result is the same.
Plz see this it is far...
I designed very simple CE amplifier with 2n2222 in PSpice. Ic is about 400mA and transistor is in linear domain but calculated g_m is far from simulated one.
g_m=Ic/Vt => g_m = 400mA/25mV = 16
ic = g_m * vbe => ic = 16 * 0.01 = 0.16 mA but ic is about 44 mA.
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