[edit] the 1Ks for LEDs when you have a whole bunch and need to limit the overall current[/edit]
hmmm, i'm not sure i understand this. I'm planning to use around 48 leds using 6 4051s. At the moment I've got only six connected with 220 Ohms resistors. I found this values by using the formula:
R = (Vs -Vl) / I
where
VS = supply voltage
VL = LED voltage (usually 2V, but 4V for blue and white LEDs)
I = LED current (e.g. 20mA), this must be less than the maximum permitted
Do I need to change the resistors if I add more Leds?
thanks