5VDC 2A Power Supply for Vehicle Electronics

[alec_t]

What is the purpose of the second 1N5402 ?

 

[bradosaurus]

My thought on that was for residual ground loop interference/AC/RF noise from the negative/ground side of the system. The ground of the system is my car chassis, which, I understand, can act like a massive antenna for all of the dirty power. Am I incorrect in my understanding?

 

[alec_t]

If all your electronic devices have their grounds connected to chassis then all their internal voltages will be referenced to chassis and even if that is acting as an antenna and chassis potential is varying wildly relative to planet Earth I don't see how it will have an adverse effect on the devices, provided they are properly screened.

 

[bradosaurus]

The voltage regulator inside my alternator has a significant amount of AC leakage. My understanding of this leakage is that it is allowing AC through both the positive and negative legs. By adding the rectifying diode onto the negative/ground leg, I see a potential to reduce residual AC on that leg. Am I still not understanding? I'm not meaning to go in circles about this, I'm just trying to apply my understanding of theory as best as I can. Will it have an adverse effect on the circuit to have that extra diode, or is it simply unnecessary?

 

[RCinFLA]

Use one of these.

https://www.amazon.com/Scosche-reVI...NO4Q/ref=sr_1_3?ie=UTF8&qid=1324952952&sr=8-3

They are switching buck power converters. You can add your filter if you like.

 

[bradosaurus]

That power supply looks like it would work, but I'm trying to build a system which is flush with the dash and doesn't take up the 12V supply. Also, the USB/cigarette adapter that I have now does 2A, but doesn't filter anything, which is the greater reason for this project. Plus, this project is only $5 so far (big thumbs-up).