Audio Electronics Tutorial

[tmbg]

the elusive decibel.

It's just a relative thing, sort of an imaginary unit. The annoying thing about decibels is the numbers are different based on whether you're talking about voltage or power.

Grab a calculator that will do log base 10 (NOT natural log, log base e), and it's easy:

20 * log10(Vout/Vin)

if you put 1 volt in, and get 10 volts back out,

log10(10/1) = log10(10)

that basically means, what power must you rase the base (10) to, to get the number in parens (10). 10 to the FIRST power is 10, so the answer is 1.

20 times 1 is 20! So, 1 volt in, 10 volts out, is a 20dB gain.

Reason power is 10 and voltage is 20 is because voltage is related to power as a square (P = E^2/R).

So, if you put in 1W and get 10W out, that's 10*log10(10/1), which is equal to 10! So 1W in, 10W out, is 10dB.

Doesn't clear up much, does it [/u]

 

[PRR]

> What the blooming hell is passing through the circuit?
A microphone pics up sound waves and converts them into what??
voltage?? (every single tutorial and book just assumes that you know this...)
If you sing louder do you get more voltage - if you sing lower do you get less voltage...?

Wait a second. Back up.

As a trumpet prof once said: It's all just AIR!

So: do you understand sound in air??

 

[yan_b]

this is excellent site for beginners, although radio oriented it's covers the basics.

http://www.radioelectronicschool.com/raecourse.html

 

[Guest]

[quote author="yan_b"]this is excellent site for beginners, although radio oriented it's covers the basics.

http://www.radioelectronicschool.com/raecourse.html[/quote]
THANK YOU!!!
Page 2 of this... covers exactly what I am after
http://www.radioelectronicschool.com/reading/reading17.pdf
I will digest and read up on what PRR suggests - with the movement of sound in air...

 

[Guest]

Resistor,
capacitor,
nullator
and
norator.
Thank you, mr. Carlin.

xvlk