This cable is kinda fascinating - it has an integrated boost converter, so you can plug it into any USB port (from a computer, battery pack, etc) and it will give you a higher DC voltage! It's a handy way to power 12V powered devices with a 2.1mm DC barrel jack from a USB port. We also have a version that provides 9V, and if you just need a passthough cable, here's one for 5VDC.

These are rated at 500mA output, but you can go a little higher, we pulled 700mA and we got a little voltage droop but it worked fine. Probably best not to draw 700mA continuously though!

Here's our measurements for various current draws when we set our bench supply to provide a steady 5V voltage

  • 50mA (12.4V output), 150mA,  83% efficiency
  • 100ma (12.4V), 290mA in, 86% efficiency
  • 200ma (12.3V): 570mA in, 86% efficiency
  • 300ma (12.2V): 870mA in, 84% efficiency
  • 500ma (12.1V): 1500mA in, 81% efficiency
  • 700ma (11.4V): 2140mA in, 75% efficiency

So, overall there's a 85% efficiency at low current draw that drops do about 80% at high current use. There's also a 3 mA quiescent current. Note that often times the USB port voltage can droop too, and in addition you may have power losses with any thin or low quality cables with high resistivity!

Technical Details

  • Cable Length: ~1.2m / ~47"
  • Weight: 34.6g

USB to 2.1mm DC Booster Cable - 12V [2778]

  • Brand: Adafruit
  • Product Code: ADA-2778
  • Reward Points: 10
  • Availability: 6
  • £11.72

  • Ex Tax: £9.77
  • Price in reward points: 200

  • 5 or more £11.14

DC Barrel Jack Adapter - Female

DC Barrel Jack Adapter - Female

£3.89

This adapter allows you to connect a barrel jack connector to bare wires

Qty: 15

DC Barrel Jack Adapter - Male

DC Barrel Jack Adapter - Male

£3.44

This adapter allows you to connect a barrel jack connector to bare wires.

Qty: 7

DC Barrel Jack 2.1mm Female / Male Extension Cable - 1.5m / 5 ft [327]

DC Barrel Jack 2.1mm Female / Male Extension Cable - 1.5m / 5 ft [327]

£6.92

Extension cord for any 5.5/2.1mm DC power cable. The heavy 22 AWG wires can handle up to 5A.

Qty: 1

USB to 2.1mm Male Barrel Jack Cable (22AWG + 1 Meter) [2697]

USB to 2.1mm Male Barrel Jack Cable (22AWG + 1 Meter) [2697]

£5.21

With this USB to 2.1mm Male Barrel Jack Cable, you can now power 5V DC powered electronics that have ...

Qty: 5

USB to 2.1mm DC Booster Cable - 9V [2777]

USB to 2.1mm DC Booster Cable - 9V [2777]

£12.21

Power 9V powered devices with a 2.1mm DC barrel jack from a USB port

Qty: 2

DC Barrel Jack Splitter - 4-Way 2.1mm [1352]

DC Barrel Jack Splitter - 4-Way 2.1mm [1352]

£7.09

Quadruple your power adapters with this wonderfully simple 4-way power jack splitter

Qty: 3

DC Barrel 2.1mm to 2.5mm Plug Adapter [2897]

DC Barrel 2.1mm to 2.5mm Plug Adapter [2897]

£2.83

Fit into a device that normally would require a 5.5 OD / 2.5mm ID plug, and lets you use a 5.5/2.1mm ...

Qty: 2

DC Barrel Connector - 5.5 / 2.1mm DC Power Plug [3310]

DC Barrel Connector - 5.5 / 2.1mm DC Power Plug [3310]

£2.93

The jack is compatible with 5.5mm barrel jacks that have a 2.1mm center pole diameter.

Qty: 5