This is very basic question but I seem can't find the answer. All out there is theory, but no practical explanation about this.

Assume I have a 10V 2A power supply. So in theory it outputs power of 20 watts. Now if I reduce the voltage to 5V with a 5A capable buck converter, can it output the same 20 watts? If so, 5V will use 4A to achieve that.

In general, can we increase the current by reducing the voltage in a power supply?


1 Answer 1


Yes, but if you use a DCDC converter for that, you need to consider the efficiency (You will lose like 10% to 20% of power for every conversion).

  • \$\begingroup\$ So, let say i have 5v3a device. Is it safe to buy 12v2a psu and convert it? \$\endgroup\$ Mar 8, 2020 at 14:16
  • 1
    \$\begingroup\$ You could but you've got two power supplies when you could just buy the right one. \$\endgroup\$
    – Transistor
    Mar 8, 2020 at 14:21
  • \$\begingroup\$ thanks! it helped clear my doubts. Marked your answer as correct. \$\endgroup\$ Mar 8, 2020 at 14:28

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