[jcranmer]

If you don't have 3 transistors wired in a way that accomplishes that, you don't violate the patent. (Actually, at least 2 transistors, the other two independent claims cover cases where you replace the third transistor with something else). You don't violate a patent by violating a loose summary of the patent, you have to specifically violate the claims in full.

[jacobolus]

Or in pictures, this circuit is the prior art: https://patentimages.storage.googleapis.com/c5/d0/e9/e4eedeb...

And these circuits are what they are patenting: (a) https://patentimages.storage.googleapis.com/91/c4/35/775214e... (b) https://patentimages.storage.googleapis.com/a1/66/be/985aac1... (c) https://patentimages.storage.googleapis.com/a8/93/45/09b4add...

[tyingq]

Yes. I'm claiming that's not novel. I wouldn't try and patent a 2 stage amp with an optional 3rd stage either.

[wbl]

If it improves on existing practice even if someone would have thought of trying it it is patentable. Think of a steel with a particular alloying element: only 92 to pick from!

[jcranmer]

But what if I want to alloy steel with livermorium?