I see a lot of examples of electronic experiments, mainly with low power devices, powered by batteries. If this could be a handy and smart solution for experiments and/or wireless/remote applications, it might not be so desirable for all the others. Also could be a pricey one, sometime.
I always use a desk power supply, with enough resources (adjustable from 0 V to 40 V and current 0 A to 10 A), but sometimes I feel better with some other approach with a smaller footprint 😉 – my desk (work table) is so tiny…
My solution is a shortcut between a desk (bench) power supply and an dedicated one. During the last months I had the occasion to play with some nice pieces of electronic named PTN78060WAS, a pretty cryptic name, doesn’t it? That is, according to data sheet, a “high-efficiency, step-down integrated switching regulator”. It is made by Texas Instruments.
Because there are two voltages, generally used with the current low power devices, 3.3V and 5V, I choose to build my tiny power supply with these two values. The standard application is shown on the first page of the data sheet and comprise a required resistor to set the output value of voltage. There is a table, on page 11, with Output Voltage Set-Point Resistor Values, therefore for 3.3V Rset = 79.3 kΩ and for 5.0V Rset = 21.0 kΩ. The final schematic is the same with these values:
Ci = 10 microF, ceramic (not polarized)
Co = 100 microF, polarized
Rset = 79.3 kΩ (for 3.3V) and 21.0 kΩ (for 5.0V)
Could be a little hard to find these exact values for Rset but the old trick with serial and parallel connection might give you a hand to figure out some closer values. Or you can use two potentiometers: 100 kΩ and 50 kΩ.