Sir, my doubt is when Vz=V2 then output voltage of opamp will be zero, then will BJT turn off? I think Voltage regulation is a continues process, when voltage should be stabilised?
I have the exact same question, did you find the answer? A Op Amp as a comparator only have or not voltage/current at output depending on the voltages at its input terminals. Unless Op Amp output acts as a transistor, that in a rude manner, we could say acts as a current dependant resistor, in this case there is a continuous regulation and not a discrete one. Regards
You can essentially already think of vz being equal to r2. Because both op amp inputs must be the same, the op amp will compare the inverting input to the zener reference, and adjust its output so that V2 *does* edual vz. Another way of looking at it is if you have the inverting input attached to the center Wiper arm of a pot that lies inbetween R1 and R2. If you adjust the pot so that the center is at the bottom and the inverting op amp input is in parallel with only R2 (we'll call this Vmax), then the op amp will regulate its output so that only V2 = Vz. If you adjust the pot so that the Wiper is at the top and the inverting input is in parallel with both the pot and r2 (we'll call this vmin), then the op amp will adjust its output so that only (vpot+v2) = vz. Say; vz = 3v, R1=1k, rpot=5k, and r2=2k. Therefore, in the vmax position ibranch = 3v/2k or 1.5mA. 1.5mA*6k = 9v 9v+3v=12v. Therefore Vout in that vmax position equals 12v In the vmin position: 3v/7k = 428.5 µA 428.5 µA * 1k = 428.5 mV 428.5mV + 3v = 3.428V Therefore Vout in the vmin position equals 3.4V. Sorry for the drawn out explanation, hope this helps
Sir I am very very happy. When I saw your edc lacture they are amazing and I am waiting for upcoming vedio finally god fullfill my wishes and thanks again 😊
Hey,can anyone out there help me clear a doubt? At first,wr are using the formula of open loop config, Vo'=A*(V1-V2) But at last,we are assuming the close loop config and saying that V2=Vz
This has been explained please watch the video from 10.00 to 10:50. Neglecting the base current Ib (which is small compared to the collector current Ic), your load current becomes equal to the collector current. Multiply load current with BJT's Uce voltage, you have the power dissipated by the BJT.
