I am developing system and I have this converter: Picture
And I need to connect this to car electronic. Where is the best spot to connect this? Can you post a picture to show me the wires.
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It looks like this is a Automotive 12.5-4.4V adapter to a PC Regulated 12.0V/5.0V ATX adapter for a motherboard (hence the chokes) with a small LED output. The first thing you need to figure out is the wiring input:
+12V Constant - The power requirement isn't too great (fused at 10A) so I'd target a large diameter +12V constant. If it were me, I'd run my own through the firewall from the battery with a 20A fuse at the battery for it, but you'd probably be just fine with the Yellow / +12V constant behind the radio or at the ignition switch.
Ignition/On - The trigger wire is going to switch it on/off, so I myself would put it on a switch I put somewhere, an On/Off/On switch with +12V constant on one side and +12V ignition on at the other. This way I could manually switch it on, off, or on when the key is in.
Ground - Run it back to the negative battery terminal if you're a wiring nazi like me, or just crimp a ring terminal on it and screw it into some dash metal with a lock washer.