How many sensors can an Arduino drive?

[TomGeorge]

HI,

@Paul_B

But on the Arduino Uno, we have a low drop-out voltage regulator. It dissipates less power in the form of heat"

Only if you use it as a low dropout, ie lower input voltage than that needed by a regular LM78XX or LM79XX regulator.
Ohms law still presides in ALL cases.

Tom...