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The current will be 5v / 10K for the pulldown, plus 5v / 1K for the PWM series resistor. That makes 5.5mA, which makes for approximately 0.2v. 0.2v + 0.7v is safely under for the HC74 family to be considered low. I see what you mean, though.
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Hi Paul, I don't think your calcs are quite right here. The resistors do indeed add in series, but the current therefore drops.
Anyway I think this is how it is ..
(approximated I/Os as 25R source / sink resistance)
PWM !CLEAR D3Anode D3Kathode (Volts)
LO LO 0 0
LO HI 0 5
HI LO 0.8 0.1 PWM source 4.1mA, !CLEAR sink 4.0mA
HI HI 4.5 5 PWM source 0.45mA
The above of course assumes that the I/O's were set as outputs! LOL.
cheers Rob