Hi,
A few questions:
- What do resistors do? Resistors take up the extra voltage you don't need right? But isn't this is wasteful? It's like this: I want one book, but the store has 10 of them. So I buy them all, and throw away the 9 I don't need (the garbage bin is the resistor). I ask, why not just buy 1 book in the first book (ie. bring less voltage into your circuit). Or does voltage not matter, and current is what really matters?
I want to control LEDs with the parallel port.
- So I'm thinking, I'll draw power directly from the 8 pins of the parallel port, to light 8 LEDs.
- Apparently the parallel port gives +5v. Does that mean each pin gives that much? Do I connect resistors with the LEDs, in series (ie a common resistor) or in parallel? A minimalistic schematic for the parallel port LED setup would be nice.
- Why are there 8 ground pins on the parallel port, isn't one enough, and all ground connections could that pin?
- What's this about current rating? I heard something about 12mA current rating on the parallel port. Is that the max current that can be drawn from each data pin?
I'm missing some basics here it seems. Your help is appreciated.
A few questions:
- What do resistors do? Resistors take up the extra voltage you don't need right? But isn't this is wasteful? It's like this: I want one book, but the store has 10 of them. So I buy them all, and throw away the 9 I don't need (the garbage bin is the resistor). I ask, why not just buy 1 book in the first book (ie. bring less voltage into your circuit). Or does voltage not matter, and current is what really matters?
I want to control LEDs with the parallel port.
- So I'm thinking, I'll draw power directly from the 8 pins of the parallel port, to light 8 LEDs.
- Apparently the parallel port gives +5v. Does that mean each pin gives that much? Do I connect resistors with the LEDs, in series (ie a common resistor) or in parallel? A minimalistic schematic for the parallel port LED setup would be nice.
- Why are there 8 ground pins on the parallel port, isn't one enough, and all ground connections could that pin?
- What's this about current rating? I heard something about 12mA current rating on the parallel port. Is that the max current that can be drawn from each data pin?
I'm missing some basics here it seems. Your help is appreciated.