What type of signal is coming from a 3.5mm audio plug?

does it create alternating DC voltages? (for example, alternating from +50mV to +200mV)
or does it create only AC voltage (without standing DC) (for example, alternating from +100mV to -100mV) ?

(when referred to the 'ground' wire on the 3.5mm plug which is the thickest connection, closest to the wire itself).

If it's only AC without standing DC on it, then how come the TEA2025B microchip can work fine when connecting it directly to the input pin?
because that would mean the input pin would have no problems with negative voltages applied to it... (with the negative voltages, I mean something like -100mV, coming from the AC input signal).

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sooraj6193 years ago


auttam4 years ago
can anybody tell me pls that by the output of that jack we are able to blink led or not or we can send it as remote or not??? and if yes then how???
samaddon4 years ago
First thing is what are you considering i the jack is for head phones then there are three wires one of golden color and two of red blue or any other color the golden wire is the negative and the two colored wires are for the the positive terminals .( left and right audio ) in headphones case they emit and very very low voltage of 0.5 to max 2.00 volts and it's for is dc analog means the current is dc but it's analog and it's frequency depends on the type of sound you are listening.
if you will supply 2volts constant to the sound will be of same frequency and less volume! and when you are considered about a mic jack it has only two wires coming out when you will cut it's wire in this case when you speak something the two wires get connected with each other in the frequency you are speaking it's just like a switch which switches on and off as the frequency you are speaking!
i hope this will solve your problem! see ya !
frollard5 years ago

from the looks of it it's ac based around 0v ground
The input is AC coupled.
aelias365 years ago
Read this: