Based on the XLE4005E1 regulator, this handy little circuit will accept an input voltage of 4.0-40 volts DC, and can produce an adjustable output voltage of 1.25 to 37 volts DC.  The output is adjusted via the small brass screw on the blue pot at the top edge of the board. This version also includes an on-board display that can be toggled back and forth between the input and output voltages.  Small pushbutton switches on either side of the display are used to toggle the display, and LEDs on either side indicate which voltage is currently being displayed.  The display can be toggled on and off to conserve power. and large solder pads on each end of the board make connection to the regulator easy.
 
This circuit is short-circuit protected, has reverse polarity protection, and has a thermal shutdown function built in.  Very accurate, this is a handy tool for the workbench, as well as a useful to include inside a model when you want to be able to monitor the system voltage with just the touch of a button.
 
DOWNLOAD: Adjustable Regulator with/Display Instruction Sheet