Having finally gotten the hang of 555-timer circuits (i think) I thought I'd expand my knowledge a bit by trying to incorporate some binary counter ICs and a comparator. I create a circuit that I think should roughly count seconds using two 4-bit counters. I'm also using two 4-bit comparators to determine when the count has reached 59. At that point I want to turn on a transistor.
I got confused however when trying to figure out a resistor value for the transistor base. I went to
the datasheet for my comparator to see what the current limit is on it's output and it listed a bunch of negative values for the output high and also no maximum value. I was planning on using a 5V source for my circuit, and if I am understanding the datasheet correctly that means the output pin in a high state has a typical current of -1mA.
I did a bunch of reading regarding negative current, sink vs source current, active high vs active low, etc and so far things are not much clearer to me than before. If my understanding is correct the the datasheet is saying that roughly 1mA would be provided by the comparator to drive the transistor. Does this also mean I don't actually need a current limiting resistor on the transistor base as the current is already limited?
Would appreciate any insight into this datasheet. I'm having a hard time understanding what it's saying and what it means for my circuit planning.