Re: Blues Blaster Mic - Capacitor

[timm@xxxxxxxxxx (Tim Moody)]

Elliot,
    Pretty close. Had I seen the original post, I would have responded.
Actually there are only a couple of thing that need clarification:

:The cap is there as a filter.  A cap appears as an open circuit to low
:frequency signals and a closed (or short) circuit to high frequencies.
 Actually a capacitor blocks DC and passes AC which is essentially what you
said. Depending on any given resistance that is coupled with the capacitance
will determine what if any frequencies are passed.

:Not a whole lot of complex filtering you can do with one capacitor...
:either pass treble or lose treble. 
To an extent this is also true but in reality all one capacitor can do is
pass ALL AC. It takes resistence to create a filter and that filter can
either be a high pass, low pass or band pass. In other words it can filter
out the highs, leaving lows and mids, filter out the lows, leaving highs
and mids or filter out the lows and highs, leaving mids(band pass). Most
mics end up with the cap and a volume pot wired as a band pass circuit. The
band of frequencies that is allowed to pass depends on where you volume pot
is setting. There's an old electronics formula, that I have to state
verbosely here due to the lack of the pi symbol, that states: Frequency is
equal to 1 over 2piRC( that's 2 pie RC) where R is the resitance of the pot
and C the value of the cap. So as resistance varies so does that value of
frequency to pass thru the filter.


Tim Moody