I want to buy a power supply that is good both for my PIC16 environment (breadboard with 3.5V - 5V power bank) and for my raspberry 3PI.

Than I choice a 5V 3A power supply with a USB exit from Amazon:


but, reading product details, I see:

Input: 100-240V 50-60Hz 0.5A

Output: 5V 3A - 9V 2A - 12V 1.5A

I can't understand output values, there isn't a button to adjust the voltage/amperage!

How do I know it won't burn my cards??

Thank you

  • 1
    There must be some way to select from the different voltages. Don't worry about amperages, those are just the max that it can output, your device will draw what it needs. If concerned about specs, function, reliability, etc, however, then I would recommend, don't buy junk from amazon.
    – Glen Yates
    Commented Dec 3, 2019 at 21:34
  • 1
    Thanks a lot for your reply! Did you see the power supplier (clicking the link)? It's a small device without any button or output regulator.. do you think I have to open it and set some jumper inside?? Commented Dec 3, 2019 at 22:16
  • If you need 3.5 to 5V, why are you looking at a power supply which delivers 5-12V? Commented Dec 6, 2019 at 9:17

1 Answer 1


That adapter's description says it supports Qualcomm's Quick Charge technology. The QC technology communicates with the device being charged and automatically selects 5, 9, or 12 volts, depending upon what the device can accept. My first thought is to return it and order a power supply rather than a charger. However, if it's connected to a "dumb" USB device, it will almost certainly deliver only five volts. If you have a multimeter, you can test the output voltage.

  • 1
    @CoderJammer If this answer your question then you should accect the answer with a click on the tick on its left side. Otherwise the question will pop up again and again ...
    – Ingo
    Commented Dec 4, 2019 at 23:50

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