I'm getting wrapped around the wheels here on some basic DC theory. I was looking up pull-up resistor applications, and while I understand that the resistor is needed to keep from shorting TTL to 0v, I'm confused as to how it sends proper voltage to the input pin.
This is more about voltage drop across resistors, and what voltage is on the "other side" of the resistor. In a voltage divider circuit, as I decrease the value of R1, the output voltage increases. This makes sense to me, because lowering the resistance of R1 is getting me "closer" to just a wire supplying the input voltage. But I've also read, that a low value resistor (10 ohm for example) will have a big voltage drop and not much voltage after the resistor.
Thinking about the pull-up resistor, a high ohm value is used (say 100k ohms) to draw a low amount of current at a logic 0 state, but also have a small voltage drop so the input pin of the IC will have pretty close to 5 volts at a logic 1 state?
I don't see how pull-up resistors work when I compare the theory to voltage divider circuits?
Also, I think I overthink the way voltage behaves in circuits. It's more important how the current behaves.
Any coaching is appreciated!
Have a good night (or day if you're out west)
This is more about voltage drop across resistors, and what voltage is on the "other side" of the resistor. In a voltage divider circuit, as I decrease the value of R1, the output voltage increases. This makes sense to me, because lowering the resistance of R1 is getting me "closer" to just a wire supplying the input voltage. But I've also read, that a low value resistor (10 ohm for example) will have a big voltage drop and not much voltage after the resistor.
Thinking about the pull-up resistor, a high ohm value is used (say 100k ohms) to draw a low amount of current at a logic 0 state, but also have a small voltage drop so the input pin of the IC will have pretty close to 5 volts at a logic 1 state?
I don't see how pull-up resistors work when I compare the theory to voltage divider circuits?
Also, I think I overthink the way voltage behaves in circuits. It's more important how the current behaves.
Any coaching is appreciated!
Have a good night (or day if you're out west)