Not that I am aware of.

So when I know the gain, what is the next step?
Thanks a lot for your comments and sorry if I m asking novice questions

 

So when I know the gain, what is the next step?
Thanks a lot for your comments and sorry if I m asking novice questions

Next, work out the base current. Then ask yourself if the previous stage can provide enough current.
If the answer is "no" then you need to add additional devices to give more gain, like @crutschow said in post #13

 

is there a specific graph in the datasheet that denotes the gain value for a certain amount of voltage?

Not normally.
And as stated, you want to use the minimum gain value, not the nominal that curves often show.

 

Next, work out the base current. Then ask yourself if the previous stage can provide enough current.
If the answer is "no" then you need to add additional devices to give more gain, like @crutschow said in post #13

Ok so lets imagine that for a 100 mA base current we get a gain of 25, meaning that the output is 250mA. What other voltage params should I take into consideration. For example. should the Vce be saturated etc...

 

Not normally.
And as stated, you want to use the minimum gain value, not the nominal that curves often show.

Understood,
in this table it is written Vce = 2V. So is this the minimum Vce or what happen if the Vce is different, how does the gain changes?

 

What you want to do is quite simply impossible. Changing the bias on the transistors changes the effective resistance which will lower the current, but there is nothing you can do with that circuit to increase the current.

That does not sound entirely correct . . .

If we remove the redundant (error source) "Voltage Follower" we got the Gain 3x amplifier . . . which due the particular BJT power gain stage has zero crossover distortion . . .

if we replace the bjt stage with highly sophisticated dc2dc module that has a capability to ramp sufficiently fast in response to the (what it seems to be) square wave stimulus - then what the OP asks is doable . . . if he can find sponsors to this project

the alternative is simply to provide a higher supply and use the "Voltage follower" as down-scaling stage to add current

 

That does not sound entirely correct . . .

If we remove the redundant (error source) "Voltage Follower" we got the Gain 3x amplifier . . . which due the particular BJT power gain stage has zero crossover distortion . . .

if we replace the bjt stage with highly sophisticated dc2dc module that has a capability to ramp sufficiently fast in response to the (what it seems to be) square wave stimulus - then what the OP asks is doable . . . if he can find sponsors to this project

the alternative is simply to provide a higher supply and use the "Voltage follower" as down-scaling stage to add current

That is essentially what @Alec_t said in Post #2, and I do not disagree with what you propose.

 

if the Vce is different, how does the gain changes?

An increase in Vce will cause a slight increase in Ic due to the output conductance of the transistor (hoe).
This will look like a small increase in the gain.
Normally the change is small enough that it can be ignored, compared to the normal variation in current gain from other factors.

 

That is essentially what @Alec_t said in Post #2

besides that - i did get your point . . . only wanted to emphasize/remind that outside the "box" it's possible

it pretty much look like an inside the bubble case when you (OP) default(s) to a certain method and are temporarily unable to see other methods avail.

a kind of an overworking stress . . . and a quite typical situation i've and often found myself at

 

Thanks all

 

BTW I posted another post but got deleted due to double posting. What do they mean?

 

BTW I posted another post but got deleted due to double posting. What do they mean?

Another post on the same subject is not allowed.

 

I have another question about adding a current follower to this circuit. So do I add it here?

 

I have the below circuit and when I add the current follower op-amp circuit to my circuit it doesn't work. If I added an ideal op amp it works but when changing it to a realistic op amp it doesn't. What would be the problem?
Realistic:

Ideal:

 

166V output from VE4?

 

166V output from VE4?

Ohh yes I didnt notice that. The real op amp output wont reach this voltage levels.
This circuit current reachs up to 800mA. But I don't think that is it a good idea to put an op amp with an output current of 800mA or supply high voltage.
So is there any other possible solution to solve this problem?

 

Not quite sure what VE4 is actually meant to do.
It will try to maintain the non-inverting input at 0V, so why not simply connect the bottom of Rw to 0V ?

 

Not quite sure what VE4 is actually meant to do.
It will try to maintain the non-inverting input at 0V, so why not simply connect the bottom of Rw to 0V ?

The VE4 is a -22V source.
If I connect the Rw to GND, no current will flow to the current follower circuit. I am trying to find a way to convert the current flowing in the circuit to voltage for measurement reasons.

 

The VE4 is a -22V source.
If I connect the Rw to GND, no current will flow to the current follower circuit. I am trying to find a way to convert the current flowing in the circuit to voltage for measurement reasons.

Use a small value of shunt resistor, say 1Ω or 0.1Ω, and measure the voltage across it. That would work with a multimeter with a decent mV range. If you are measuring it with a A/D amplify the voltage with a INA180 or similar.

 

INA180

That's interesting. So can I say that current-sense amplifiers are better than current follower op amp for current sensing and voltage reading? Or does it depend on the case?