voltage divider resistor values

[fogwolf]

EDIT: Found it - http://www.diystompboxes.com/smfforum/index.php?topic=70581.0

I want to mod a circuit and need to tap off 4.5VDC from a 9VDC supply. I know I was just reading about this somewhere recently but can't recall what it said - what are the things to consider when picking the resistor size to get 1/2 a voltage value? Since both resistors are the same ohms what's the difference between picking, say, two 10K resistors versus two 100K resistors? When does this matter and when does it not matter (or does it always matter/always not matter)? In case the context is relevant, the mod I'm doing is tapping off an audio signal and putting it through a dual op amp - the 4.5VDC is for the + input of each op amp (not to the Vcc pins).

[GibsonGM]

High (relative to the load) current flowing thru a resistive voltage divider gives a more stable voltage as the circuit draws on it.   This is balanced with efficiency (higher values = less current flowing thru the divider and more thermal NOISE from the resistors).  Generally the values run from 10k to 100k...10k to 47k seem 'right' in your application...

[fogwolf]

Thank you!

[R.G.]

http://www.geofex.com => Circuit Sweepings => Designing bias networks to provide Vbias in effects