True or False: An amplifier creates new energy out of thin air to make a signal louder.
False
True
The "Gain" of an amplifier refers to the ratio of output signal to input signal.
False
True
A pre-amplifier is usually the very last stage in an audio system before the speakers.
True
False
Amplifiers can be found in devices other than just guitar amps and stereos.
True
False
In the context of amplifiers, what does the term "Distortion" mean?
An unwanted change in the waveform where the output does not perfectly match the input shape.
What is the main difference between a Transistor and a Vacuum Tube amplifier?
Transistors use semiconductor material (solid-state), while tubes use heated filaments in a glass vacuum.
What do we call the "efficiency" of an amplifier?
The ratio of useful power output to the total power drawn from the supply.
If an amplifier has a gain of 10 and the input is 2 volts, what is the output?
20 volts
Name three common "Classes" of amplifiers.
Class A, Class B, Class AB, Class C, or Class D.
What are two advantages of a Class D amplifier over a Class A amplifier?
They are much more efficient and produce significantly less heat.
List two components often used as the "active element" in an amplifier to provide gain.
Transistors (BJTs/MOSFETs), Vacuum Tubes, or Operational Amplifiers (Op-Amps).
What are the three main terminals of a Bipolar Junction Transistor (BJT) used in amplifying?
Emitter, Base, and Collector.
In an amplifier, what is the "Signal-to-Noise Ratio" (SNR)?
A measure that compares the level of a desired signal to the level of background noise. (The higher the ratio, the cleaner the sound).
What is the purpose of a Heat Sink in a high-power amplifier?
To dissipate the heat generated by the transistors or tubes to prevent the components from burning out.
Which specific type of amplifier is designed to only amplify very low frequencies, usually below 200 Hz?
A Subwoofer Amplifier (often used in car audio or home theaters).
What does "Clipping" look like on an oscilloscope, and what causes it?
The top and bottom of the waveform look "flat" or cut off. It happens when the amplifier is pushed beyond its maximum voltage capability.
