Learning module
Amplifiers
Amplifiers use a small signal to control a larger signal for audio, sensors, and communication.
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Mark lessons as complete as you work through the bench checks, then use the quiz to test the ideas.
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Amplifiers
AC vs DC
DC flows one way. AC changes direction repeatedly and is used for power distribution.
Resistors
Resistors limit current, divide voltage, set bias points, and turn electrical energy into heat.
Capacitors
Capacitors store charge, smooth supplies, pass changing signals, and block steady DC.
Inductors
Inductors store energy in magnetic fields and resist changes in current.
Transformers
Transformers transfer AC energy through magnetic coupling and change voltage by turns ratio.
Amplifiers
Amplifiers use a small signal to control a larger signal for audio, sensors, and communication.
Speakers
Speakers use a voice coil in a magnetic field to move air and create sound.
Radio Waves
Radio uses electromagnetic waves to carry information through space.
Solar Basics
Solar panels provide variable DC power that needs regulation before charging batteries.
Visual schematic
Speaker crossover split
A capacitor protects the tweeter from low frequencies while the woofer handles the lower band.
TP1: amp output
TP2: tweeter high-pass
TP3: speaker polarity
Interactive lesson workbench
Move the controls and watch the idea change.
This is a simplified teaching model for Amplifiers. Use it to build intuition before opening the calculator, lab, or real bench.
What changed?
120 mV times 12x gain wants 1.44 V peak. With a 9 V supply this lesson model clips around 7.20 V peak.
Guided lesson coach
Work through Amplifiers like a bench exercise.
First, name the job of the part or idea.
Say what it controls, stores, blocks, transfers, or protects. If you can explain that plainly, the formulas become much easier to use.
Start here
Build the mini amplifier project and use a phone or signal generator at low volume as the first test source.
Key ideas
Amplifiers increase signal voltage, current, or power depending on the circuit job.
Biasing sets the operating point so the signal can swing cleanly.
Coupling capacitors can pass audio while blocking unwanted DC.
Output stages must be matched to the load impedance and kept within heat limits.
Useful formulas
Voltage gain = Vout / Vin
Power = V x I
Speaker power estimate = Vrms^2 / R
Bench checks
Start with low volume and a current-limited supply.
Check DC voltage at the speaker output before connecting a speaker.
Listen for hum, clipping, and heat as early fault clues.
Common mistakes
Connecting too low an impedance speaker.
Forgetting shared signal ground.
Turning gain up before checking supply polarity and wiring.