Adapter current

Hi guys,

I have an adapter which I use with my Shruthi that is 12V DC (which is within the required range), however it says 500mA, which is higher than the 300mA written on the Shruthi.

Does this mean that the adapter always supplies 500mA, so the current is too high for the Shru

Nope, the adapter supplies as much as the shruthi needs, UP TO 500mA… Go ahead, plug 'er in !

It only means it CAN deliver 500mA, not that it pushes this thru the Device.

Check if its really 12V, some cheapo PSUs have much more when not fully loaded so they can reach specification at maximum load. Anything above 14,5V will instantly fry your LT1054. You might want to look for a regulated 300mA 7,5V Swithing Power PSU, with 12V your Regulators will run so hot you will want to have holidays in Desert Valley…

I will look and see if I have a 9V one instead. I wish there was the warning about unregulated power supplies in the guide that came with the Shruthi. I used it for more than 30 minutes earlier today, so hopefully it was alright, but I don’t want to take any chances.

Thanks for the replies!

You can always test what the adapter does under load by putting a 5-10K resistor between the +/- and measuring the voltage

@adamd1008
If it works, it works. Guess why i cut all these HexHoles into the sides :wink:

@fcd72 Yeah I guess :slight_smile: but I generally stick to the maxim: “the hotter it runs, the less lifespan it will have.” I’ve got a 9V 1A switching PSU (that’s OK, right?) and life sounds pretty good.

In winter you might consider heat dissipating as a bonus auxiliary heater, but apart from that it’s a 100% waste of energy. I like to get a plug that’s a bit heftier than really neccesary, a 600mA or so, and run it at 7,5V or 9V, the lowest that will work reliably.