Newsgroups: rec.audio.tech
Subject: Re: Voltage on PC - microphone jack
References: <[email protected]>
[email protected] (Fredrik) writes:

> I'm trying to figure out if one can safely assume that almost all PC
> sound card nowdays have 1.5 Volt on the microphone jack.


You can assume that PC has some powering on the microphone 
connector, but you can't assume that all PCs have exactly 1.5V 
power source. 

The typical PC microphone output has heavily power limited +5V 
power feed out of it (the voltage drops to something like 1-3 volts 
when electret microphone is plugged to it typically). 

This powering method is to my knowledge standardized in 
Intel PC building "standards" PC 97 / PC 99 in multimedia 
specifications. Practically all built-in PC sound systems 
and soundcards follow those specifications.

More details can be found at 
http://www.epanorama.net/links/pc_sound.html#interfacing

> The reason I'm asking is because my company is selling a karaoke
> product for PC that includes a condensor microphone that requires
> 1.5V.
> 
> The company manufacturing the microphone of course says it should work
> fine on most computers, but I would like your opinion on it as well...
> 
> Any help on this is much appreciated!
> 
> Thanks!
> /Fredrik

-- 
Tomi Engdahl (http://www.iki.fi/then/)
Take a look at my electronics web links and documents at 
http://www.epanorama.net/