In a recent experiment I performed after fielding another's question in another thread (CMOS NAND), I wired a cd4001BE NOR gate as follows.
Vdd = 6V/5A source
Vss = 0v
A=B=X=Vss
To my surprise I found that the current drawn from the supply was only around 8mA.
6v/8mA=0.75x10^3 = 750Ω
Where did that 750Ω limitng resistor come from? In my research, the highest resistor I've found is 15-30Ω + Rds_on in series with a CMOS output (via cd4007 datasheet.)
What gives? Is an on p-channel MOSFET really 720Ω? (According to a cd4001 datasheet, the 1/4 cd4001 is actually a NAND with inverters on its inputs and output. So, it's really just a single on p-channel device when its inputs are low, not a series.)
Logic gates aren't designed to drive relays and motors - they're designed to drive other logic gates. When you consider that the input capacitance of a 4000 series gate is typically 5pF, a fanout of ten (50pF) would yield a risetime of around 50ns - plenty fast for the specs of the CD4000 series.