Thats what I get 07.1

sorry I didn't see the "minus" sign... measuring again I get 7.4 and 6.9 = 0.5V

 

For what? be precise

VB, VE or VB-VE?

Give VB and VE please

 

Sorry I misread your picture I thought you meant VB - VE both had to be 0.7V not one minus the other. Look above. I got 0.5V

 

OK, so:

If VE ~ 7V, IE = 14mA, which means re = 25/IE(mA) = 1.8Ω.

And rπ = 1.8 * BETA.

(rπ + RL' * BETA) = BETA * (1.8 + 0.33K) ~ BETA * 0.33K

And Zi = RB // BETA * 0.33K = 0.34K // BETA * 0.33K

If BETA = 100, you have Zi = 15K (see my post #75)

In LTSpice I checked the default value of BETA = 300 for that transistor. With BETA = 300, Zi becomes 20K.

So most probably the BETA of your transistor is more 100 than 300.

In this case, to me, the given measures are consistent. As you know, Ai = Zi / RL. If you want to increase the gain, you must increase Zi (e.g. you could choose bigger values for R1 and R2) or decrease RL.

 

Yeah it's good enough man, considering all these machines arent exactly accurate. When I measure my emitter on these test sets I get a gain of 8...but when I use the digital osciliscopes I get 18. So the current gain is probably larger than 15 its just the machines. Either way it works.

Again thank you very much for your help, time and patience.