HF2 – 24V Variable DC Power Supply


Hui Gardens HF2 24V variable DC power supply prototype is meant to power small electronics from hobby 3V3 and 5V sensors (e.g., Arduino and Raspberry Pi) to 24V industrial process 4-20mA transmitters. Housed in its own Pelican 1200 case, it can withstand rough transport and handling. It takes AC or DC input from an external source up to 30V AC/DC and outputs a rectified lower DC voltage. The input is a 2.1mm barrel jack that should be easy to find at an electronics parts store.

Due to the experimental intended purpose of this DC power supply, a 0.5A breaker is put in place instead of a fuse that requires replacement.

Hui Gardens HF2 features a 2W potentiometer for adjusting voltage output which should be plenty even when powering 4-20mA transmitters. Since it relies on setting of voltage via your multimeter prior to use, it is as accurate as your multimeter and there is nothing to calibrate.

The output comes via a binding post, so you can use banana plugs or bare wires. A standard spaced red and black post was chosen so that the fancy integrated two conductor leads can be used as well.

The red toggle switch cover and badge of Chairman Mao is the pièce de résistance taking this variable DC power supply to a new level.

Specification Value
Maximum Voltage Input 30V
Maximum Voltage Output 24V
Maximum Current 0.5A


This working prototype had been superceded by the Hui Gardens HFX electrical test set