AMP I.10 – The Common Source Amplifier

Introduction Just like bipolar junction transistors, we also have three classical amplifier configurations for JFET that lay the foundation for all JFET amplifier theory.  They are the Common Source amplifier, the Common Drain amplifier, and the Common Gate amplifier.  In this chapter we’ll discuss the Common Source amplifier. JFET Particulars Let’s recall the small signal … Read more

AMP I.8 – The Cascode Amplifier

Introduction We’ve seen that a Common Base amplifier has a bigger bandwidth than the Common Emitter amplifier as it doesn’t suffer from the Miller Effect.  However, the low input resistance of the CB amplifier can be a problem: it can draw lots of current from the preceding stage, greatly “loading” it and altering its intended … Read more

AMP I.7 – The Miller Effect

Introduction So far, we have studied BJTs and their different configurations, isolated from any other circuitry.  We’ve learned a lot, and we’re much further along than we first started.  However, until now we haven’t given much thought as to our circuit’s frequency response, and how differently that can behave depending on our input signal’s frequency.  … Read more

AMP I.3 – BJT Classical Configurations

Introduction Now that you have the basics needed to understand and analyze transistor circuits, let’s continue our study with the classical textbook configurations of BJT amplifiers.  You’ll find these in every course and textbook that deals with amplifiers, though not always with great explanations. The following circuits are textbook circuits, and while you may find … Read more