ron h, thanks a lot.can u send me the ltspice circuit file?i want to simulate to see the output.
Change R4 to 3k to get Ic(Q8)≈200μA. Ic(Q8)≈Vbe(Q9)/R4. Vbe(Q4)≈0.6V.what is the gain of this circuit?does the current sink provide 200uA in this case?how to modify to obtain other desire current source?
I was overly harsh. No harm done.i already cite the source at other forum.sorry again, Ron H.
Are you aware that the pinout of the two transistors are different? If you have the pins connected incorrectly, the transistors may burn up. See attachment.finally i enter the lab to verify the circuit, but no luck though. cannot get any result.i have include several suggestion and comment made by my lecturer. see the attachment. so i would like to ask you whether those suggestions make sense or not?
most weird thing is when i feed some signal let say 1 Vp at the +ve input,but when i check the +ve input using oscilloscope only mV range i get. not sure what is going on.
second thing is the lab assistant say there should be 0 V at the Vo if 0V is connect in common mode to input. so i connect the +ve and -ve input and ground it, but the output transistor burn.
I didn't know the pinout. I looked up the datasheet.oh,the pin out is different for each of them. i didn't aware about that.i use same pin out as 2n2907.no wonder it will burn up.they didn't provide data sheet so only can make guessing.
I don't know what this means. What do you mean by "them"? Do you mean resistors?one more question,how do you actually knowing what value should be substitute for each of them?got any formula or based on experience or based on simulation?
If you mean the frequency compensation capacitor and resistor, I chose them by a combination of experience, and trial and error in simulation.the resistor and capacitor.how you know what value is suitable for them?calculation?
The power supply bypass capacitors do nothing in a simulation, because they are in parallel with batteries, which have zero impedance. In the real world (e.g., a breadboard, or a PC board), the power supply wiring and PC board traces have series resistance and inductance. These can cause undesirable effects in electronic circuits (not just op amps). Power supply rails should always be bypassed on the circuit board. In circuits with multiple ICs or discrete circuits, you will probably need multiple bypass capacitors for optimum performance. Common practice is to decouple each IC. In your circuit, there are no ICs, but the op amp still needs to be decoupled.what is the purpose of 100nF capacitor at vcc and vee?can you send me the spice model of pn2907 to me?i didn't have it in my ltspice library.
.model PN2907 PNP(Is=650.6E-18 Xti=3 Eg=1.11 Vaf=115.7 Bf=231.7 Ne=1.829 Ise=54.81f Ikf=1.079 Xtb=1.5 Br=3.563 Nc=2 Isc=0 Ikr=0 Rc=.715 Cjc=14.76p Mjc=.5383 Vjc=.75 Fc=.5 Cje=19.82p Mje=.3357 Vje=.75 Tr=111.3n Tf=603.7p Itf=.65 Vtf=5 Xtf=1.7 Rb=10 mfg=Fairchild)