How do amplifiers work?
In: Technology
They take an input and give out an output bugger but the same shape.
This can be done in a million different ways for sound, electricity, a million different types of mediums. Im going to assume you meant an electric signal amplifier, as that’s most commonly referred to as just an “amplifier”
Generally there’s a separate higher power source, and theres a transistor.
The signal itself isn’t getting bigger, it’s used as a control to tell the transistor how much of the higher power source to let through at a time.
Think of how the gas on your car works. You’re doing relatively small movements of your foot on a pedal. There aren’t gears directly turning your foot into motion, instead there’s a high power source (a tank of gas) and your foot is just controlling a gate saying how much gas to let in at once. But because the power generated depends on how much gas is let through, the graph of your engines power output will look like the graph of the motion of your foot, just on a way bigger scale
It’s complicated math, and pretty dependent on the actual circuitry and specific type of amplifier.
The most simplistic way to describe electronics amplifiers is your input signal is being used as a switching signal to make a more powerful circuit turn on and off such that the output is a more powerful version of the input.
Imagine if you had a morse code switch wired up to a lightning generator. Your finger presses the switch, which is a fairly small force, to complete the circuit on the lightning generator and create a much larger one. (Ignoring charging times and all that jazz, but it’s a simple visual way to describe the concept)
to put it very simply
they take the sound waves of the music/instrument.
and then send the sound waves back out again, but this time pumping them up with extra energy in the speaker making them louder.
I think of it as acting like a gate that controls the flow of a huuuuge stream.
Say you’ve got this tiny signal… a faint whisper. Electronically, you can detect the signal, but it is very small. If you connect the rise-and-fall of that signal to the rise-and-fall of a gate… then the small signal is converted into a signal that is equivalent to the size of the stream that is behind the gate.
A basic electrical amplifier is made up of two parts: an op-amp to provide “gain”, and a voltage divider to use feedback to reduce the gain to the right amount.
An op-amp has two input pins (`+` and `-`), and a separately powered output pin. If there’s any difference in the input pins, it tries *very* hard to make the output many times bigger than it. You can assume “infinite”, but real-world op-amps vary from 20,000 to 200,000 times bigger.
Most things do not need to be 200,000 times bigger. That’s where the voltage divider comes in. You wire it from the output to the `-` input, dividing the voltage along the way. So if the input signal at `+` is 1V, and the divider is 10:1, then the output will get driven up until the `-` input is *also* at 1V. And since it’s a 10:1 voltage divider, the output voltage gets put at 10V, so the overall gain is 10.
(how the op-amp itself works is way outside the scope of ELI5, if you’re an Electrical Engineering major in college you’ll go over it in like, your 2nd or 3rd class IIRC. How the circuit works with an ideal op-amp is in your *first* EE course, so I can in principle ELI5 it)
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