For questions about component-level electronic circuits, tools and equipment.
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This image below is not the PSU I have, just something I dug up, but it suggests a purpose for 4-pin connectors that I can understand, as there are two different voltages supplied:
Although I don’t understand what it means to have prohibited signs on two of the pins. Is that a suggestion that they be used as negatives, despite being called “gnd”?
In this photo it’s simply saying if you need 12v on the right dont use this power supply because it’ll go into the 5v side of whatever you’re powering. Keep in mind these are just standard din connectors. They’re not tied to a standard pinout and are used for all kinds of things
WRT your op it’s about current capacity of the connector. If I have a device that needs 12v at 8 amps but each pin is rated for max 5a I can deliver 12v at 4-5 amps through two pins and tie them both to the power rail on the pcb to get a full 8a capacity
If I have a device that needs 12v at 8 amps but each pin is rated for max 5a I can deliver 12v at 4-5 amps through two pins and tie them both to the power rail on the pcb to get a full 8a capacity
That’s interesting and perhaps it explains why there would be two 12v pins (so they can be combined to give double the current). But the question remains as to whether “5A max” on the label implies 5A max per pin, or 5A max total when combined.
Generally, assume the lower result unless explicitly stated otherwise. If there are two pins supplying 12vdc but only a single output rating, then the assumption should be that the PSU produces a single 12vdc rail, and the total of both pins is 5A max. It is implied (unless otherwise stated) that the full rating of 5A can be drawn from just a single pin.
From a marketing perspective, if there were multiple output rails, they have an incentive for them to list them out in detail. ATX PSUs for PCs do this.
From a safety perspective, it would be downright irresponsible to design a connector on a finished product (like this standalone PSU) that has a lower per-pin rating that what the supply can offer, so any decent pre-built PSU will not have per-pin limits that are lower than the total output limit of that group of pins. As a counterexample, ATX PSUs are a component in a larger product (a computer) and so individual pin limits must be adhered to.
5A max is certainly for the adapter, not the pins. Pins are an implementation detail, that sticker is telling you what the supply is capable of.
Also, check the power rating. 60W, 12V means a max 5A output.