I am very new to electronics. I am learning as I go, and I haven't quite found the answers I need; when it comes to programming, I'm not afraid of mistakes as they happen constantly. With electronics, though, I don't want to have to buy parts again because I fried them!
I am trying to build something that has three different components in it: a 12-volt 4.3-inch LCD screen, a 5-volt Raspberry Pi, and a 12-volt custom device. I've had the idea that I can split the power I need three ways from a 12-volt power supply: one directly to the LCD screen, another directly to the custom device, and one to a 5-volt regulator, thereafter splicing into a USB cable to plug into the Pi. As I've been researching, I've noticed that people say that capacitors in the circuit before and after the regulator are mandatory to keep the current from oscillating.
Question 1: Is this three-way split with the regulator a sound idea, or am I missing something? I understand there is the potential to need a heatsink on the regulator. That's not an issue for me if necessary.
Question 2: Does my circuit require the said capacitors? If so, what kind/quality would be best? I know little about capacitors thus far. Also, I came across this component while reading another question/answer here; maybe this would be better than a regular regulator?
Question 3: Someone who is not extremely proficient in electronics but definitely better than me said that it might just be easier to use one of those 12-volt car USB charger devices instead of a regulator, which makes sense-- USB is a 5-volt world by nature, and I don't have to worry about splicing a USB cable for the Pi; wiring up the car adapter would be easy. And I have plenty of room to allow for a car adapter; the box I'm putting all of this in will be relatively empty for how large it is. Is this a sound idea? Perhaps better/easier/safer for the Pi than using either of the beforelinked regulators and capacitors spliced to a USB cable?
As for amperage, I'm still researching just how much draw the custom device and the LCD screen will need to make sure there is enough current. That's not going to be a big issue, unless there is something I am overlooking about a regulator requiring a substantial amount of amperage more than it gives out... but I don't think that will be an issue. I'm planning to get a PSU with a good amount more amperage than my setup theoretically requires-- just in case.