Hello,
I'm using an AND gate IC, AHC08 is the chip... and I'm wondering something about inputting a logic low into this guy. basically I'm tying the emitter end of a transistor to the input gate, and sending these to ground through a pull down resistor. My collector is tied directly to a 5V source.
So, here's my question. Does it matter what the value od the pull down resistor is, and can it be too high? I imagine it can be too low, cause that will short the 5V to ground when the transistor turns on.... but if it's too high... would it essentially make it look like the input to the gate is floating?
On the datasheet to the AND gate it has an Ii (input current) value of
1uA. Is this current going to be running through my pulldown resistor to ground when the transistor is off?One more question,
I have a D Flip-Flop, that says it has a IiL (current input low on the D input) of -1.6mA.... if I want to tie my input of the AND gate (and therefore the emitter of the transistor and the pulldown resistor) to the D input of the D latch, does this mean I'm going to have -1.6mA going through my pull down? In this case I would have to calculate a low input voltage with the pull down and figure out R.
The D Flip Flop:
Much thanks!