The 2N2222 datasheet says the high frequency is 250 MHz so our 1 GHz amp will not work! If you run the numbers and change the transistors you will find a lot of transistors will work in our circuit. Changing the E12 resistor selection will give different resistor values from one transistor to another. The E12 pack has the fewest values and the E96 has the most. For general hobby work we should not need 1% resistors.
The other thing to look at here is the input and output Z. It seems overlooking the Z factors is a common error. If I build this circuit and it works well and add a second stage exactly like it the amp will fail to function. Why? I used a 1K input and 50K output. The second stage will overload the first and 'kill' the signal.
So in order to add a stage we must set the input on the second stage to the output of the first (even more). Maybe this is why we see so many one active device circuits?
Post a Comment