PICKING UP WHERE I LEFT OFF...
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After reviewing the book on Microphones, both on this blog, and in a video report, I thought I'd share some of my meager knowledge in how they work. There are some crazy looking microphones out in the market; different shapes, sizes, etc. but they all follow the same principle of acting like a transducer [a "Transducer" converts one type of energy into another]. In the case of a microphone, it converts sound waves into varying electric signals. I say "varying" because sound is not one constant push of energy, so when it comes out on the other side, the voltage must vary as well or we would not understand a thing.
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The big question is "How does it do it?" Obviously it has to do with electronics/electricity and var
ying two variables - in this case, resistance, which then varies the voltage, and all of the magic takes place inside the microphone element. I'm not going to go over all the different elements (heck, buy that book I reviewed) because the theory is the same. Basically to vary the voltage you need a variable resistor. So how does that fit in?
-After reviewing the book on Microphones, both on this blog, and in a video report, I thought I'd share some of my meager knowledge in how they work. There are some crazy looking microphones out in the market; different shapes, sizes, etc. but they all follow the same principle of acting like a transducer [a "Transducer" converts one type of energy into another]. In the case of a microphone, it converts sound waves into varying electric signals. I say "varying" because sound is not one constant push of energy, so when it comes out on the other side, the voltage must vary as well or we would not understand a thing.
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The big question is "How does it do it?" Obviously it has to do with electronics/electricity and var
ying two variables - in this case, resistance, which then varies the voltage, and all of the magic takes place inside the microphone element. I'm not going to go over all the different elements (heck, buy that book I reviewed) because the theory is the same. Basically to vary the voltage you need a variable resistor. So how does that fit in?Well first, if you were to look into your microphone you would see a microphone "element" (a.k.a. - The Transducer). The element can be a Crystal, Carbon, Ribbon, etc. type element, but what's important to remember is that while they may be different - they basically work the same way. It's not nearly impressive as the outside of the microphone but it is the "heart". The element has a couple wires soldered to it, to complete the circuit.
If you look at my crudely drawn diagram to the left you'll see the inside of the microphone. When you speak into the mike the first thing the sound waves hit is the diaphragm - a very thin material than bends easily.Behind the diaphragm is the ingredients that make it work. For example, let's say that this is a Carbon microphone. Carbon is a conductor, and it's made up of small carbon particles placed in a container of sorts. I believe they call the container a "button".
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As you can see, there are two wires - one on each end of the button to complete the electrical circuit. With no sound waves at all, the button is a constant resistance so there's no change in voltage. This is where the diaphragm comes in. As you talk, the sound waves hit
the diaphragm and the diaphragm pushes in towards the button (remember, the diaphragm is VERY thin). As it presses against the carbon particles, pressure moves the them in a variety of ways (tighter, looser, etc.) and with each change, the resistance value changes, and with each change in resistance, we get a different voltage. If this sounds like a variable resistor, you're correct, and the circuit to the right is basically all it is! No black magic or slight of hand, just a circuit with a variable resistance that changes constantly due to the force of the sound waves. Below, you'll find my video review of the book in it's crudest stage. Once I polish it up, it will also be part of my Spring Video 2007.-
WOODY
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