What is a transistor?
A semiconductor device that can amplify a signal or act as an electrically controlled switch in digital circuits.
What are the two primary digital logic voltage states?
Logic 0 (LOW) and Logic 1 (HIGH).
What are N-type and P-type semiconductor regions?
N-type regions have excess electrons as majority carriers, while P-type regions have holes as majority carriers.
What are the three terminals of a Bipolar Junction Transistor (BJT)?
Emitter, Base, and Collector.
How does a BJT control current?
A small base current controls a much larger collector-to-emitter current.
What does it mean that a BJT is current-controlled?
The transistor turns ON when base current flows and turns OFF when base current is zero.
What are the three terminals of a Field-Effect Transistor (FET)?
Source, Gate, and Drain.
How does a MOSFET turn ON and OFF?
It turns ON when the gate-to-source voltage exceeds the threshold voltage and turns OFF when it is below threshold.
Why are MOSFETs preferred in modern CPUs?
Because the gate draws negligible steady-state current, resulting in low power consumption.
How many input combinations exist for a logic circuit with $n$ inputs?
There are $2^n$ possible input combinations.
How is an AND gate implemented using transistor switches?
By placing transistor switches in series so current flows only if all switches are closed.
How is an OR gate implemented using transistor switches?
By placing transistor switches in parallel so current flows if at least one switch is closed.
What does a NOT gate (inverter) do?
It outputs the logical complement of the input.
How can complex logic diagrams often be simplified?
By tracing signal paths stage-by-stage and recognizing gates that force fixed outputs.
Why is transistor count important?
Transistor count provides a measure of circuit complexity, and increasing transistor density enables more capable computing systems.
