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As far as the official specifications are concerned an rPi can be powered with supplies from 5V to 12 V. Typical current for 5V supply is 2A. Total power required for an rPi is 10W roughly.

Raspberry pi model 2B, 2GB ram

I have two power supplies (5V, 2A) and (10V, 1A) which one to be used so that the pi dissipates less amount of heat while in operation? Why?

If in a given scenario, one has a blackbox with a power requirement of 10W irrespective of Voltage & current (lets assume the voltage bracket of 5V to 12V and current bracket of 1A to 3A) then which power supply you would go for? and why?

Any clarification shall be appreciated.

Thanks.

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    \$\begingroup\$ This is not an engineering but a usage question. Also, you're expected to at least be able to read a spec sheet or table that says which voltages your device accepts. It doesn't accept both, so there's no choice here. \$\endgroup\$ Apr 12 '20 at 10:18
  • \$\begingroup\$ We can't answer this as we don't know which Pi model you mean so we can't look at it's input voltage regulator. Please edit that into the question. Most likely it used a switch mode regulator so in theory there can be differences in the efficiency based on input voltage, but they might be so small that is irrelevant to the 10W consumption of the Pi itself. \$\endgroup\$
    – Justme
    Apr 12 '20 at 10:19
  • \$\begingroup\$ Thanks for the input. It is a Raspberry pi model 2B \$\endgroup\$
    – Biplab Roy
    Apr 12 '20 at 10:25
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    \$\begingroup\$ "As far as the official specifications are concerned an rPi can be powered with supplies from 5V to 12 V." - Do you have a reference for that? Especially the "to 12V" part? Because I'm pretty sure that's not true. \$\endgroup\$
    – marcelm
    Apr 12 '20 at 15:50
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The official spec here https://www.raspberrypi.org/documentation/hardware/raspberrypi/power/README.md suggests a minimum supply voltage of 5.1V for an RPi2 (and other models). You may get away with just 5V as there is likely some degree of voltage regulation headroom.

You comments suggested that the supply voltage could in fact be higher at a maximum of 12V. In this case the on-board regulation is going to be working hard to bring the voltage down, dissipating a lot of heat and stressing the unit. It would work if it's in spec but it's not a good choice.

As a rule you want to go for the lowest voltage that's acceptable with sufficient current capability to drive the unit at it's peak requirement e.g. high cpu load and driving peripherals with a high current requirement like WiFi.

5V 2A is the best choice from your available options.

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