Posted January 28th, 2017 at 10:00 AM
Not strictly Arduino Tech but useful in that area the DROK SKU090029 DC to DC Voltage Converter provides a useful range of operation; 4.5V to 35V input and an adjustable output from 0v (yes 0V) to 33V.
The module only costs around £7.00 in UK. Datasheet is here
The unit has an adjustable output voltage courtesy of a two button mechanism letting you set integer and fractional part of the voltage. In addition it has a push button to toggle the output on and off courtesy of a TPCA 8016 MOSFET (RDS = 16mOhm).
No efficiency specs are provided with the module datasheet so we made our own measurements, along with case temperature, using a more realistic load of 10 ohm. No heatsink was applied to the switching regulator, a XLSEMI XL-2596 using a TO-263 package. The module datasheet warns about exceeding 1.5A without a heatsink and temperature chart clearly shows why. Ambient temperature for the test was 20 deg C.
All in all a pretty good performance for a low cost module.