An op amp. @Bordodynov's circuit is nearly as complex as a basic op amp.

The reason op amps work so well is that they use very high gain and a high ratio of feedback to control the amplification. You CANNOT do this with one transistor.

Bob

 

The reason op amps work so well is that they use very high gain and a high ratio of feedback to control the amplification. You CANNOT do this with one transistor.

Thx Bob . But let's say I'm not picky about the amount of amplification. Let's say my only objective is to push the output positive .

A clamp looks promising . So does a JFET without a coupling cap on the output.

 

Let's say my only objective is to push the output positive .

If that's all there is to your requirement, then just about anything that gives a positive output should work.

 

If you don't need any amplification, why do you need any circuit at all?

Maybe it is time to tell us where this signal is coming from and where it is going, and what you are trying to do with it.

Bob

 

As mentioned above, the source is an all-positive staircase.

I want to roughly double it's voltage, and keep it all-positive .

The reason I said "assume I don't amplify" was to break out the two requirements separately .

My sim appears to show that, in the absence of output polarizing cap (to remove DC), both JFET and BJT output a positive-only voltage. That seems promising . Maybe I can get positive-only by taking parts away, rather than adding parts. In which case, I only need to worry about amplification.

Obviously, i'm shooting in the dark, and have much more to learn about transistors

Still, transistors are supposed to amplify. My requirement doesn't seem complicated .