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The step-down adapter from above at an angle: a long black board with a USB-C socket in the middle of its far edge, a small square trimmer in each top corner beside a blank white box, a three-legged regulator on each half, a red LED near the middle, and a plus and minus mark over two columns of three pins at each end.
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This board opens in a VR headset: life-size, or big enough to stand beside, with every pin and every part named where it sits. Open this address in the browser on a headset such as Apple Vision Pro or Meta Quest.

learn.lonelybinary.com/vr/bbpwdsd
You have this

Breadboard Power Adapter, Step-Down 1.25–3.5 V

Three USB-C breadboard power adapters that plug into both pairs of rails at one end: a standard board with a 5 V / 3.3 V switch per side, a step-down that sets 1.25 to about 3.5 V, and a booster that sets about 4.3 up to 28 V. Which way round they go, why 5 V reads 4.7, and the half-amp fuse that limits all three.

Each side
1.25–3.5V, by trimmer
Regulators
2× AMS1117-ADJ
Fuse holds
0.5A in total
Start here · 01 One plug, two railsOpen the board in 3D

Both regulators, their trimmers and the twelve pins, with what each part does to the voltage on its end's rails.

Product questions & answers ↓

Same plug, different voltage

All three fit the breadboard the same way and share one half-amp fuse. Pick by the voltage your circuit needs.

See this board 5 / 3.3V, by switchBreadboard Power Adapter, Standard 5 V / 3.3 V, 3-Pack3.3 V budget: 200 mA, shared
You have this1.25–3.5V, by trimmerBreadboard Power Adapter, Step-Down 1.25–3.5 VRegulators: 2 × AMS1117-ADJ
See this board 4.3–28V, by trimmerBreadboard Power Adapter, Booster up to 28 VAt 12 V: 160 mA, both sides
The whole handbook12 articles · 55 minQuick referencePDF · 401 KBDatasheetPDF · datasheet.lcsc.comModel (GLB)GLB · 2.9 MBCAD (STEP)ZIP · 2.2 MBDrawing (PDF)PDF · 1.4 MBDrawing (DXF)ZIP · 107 KBPinout and specsThe pin table, and the questions people ask first
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Breadboard Power Adapter, Step-Down 1.25–3.5 V

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Email us or reply to your order, and quote bbpwdsd — that identifies the product. If something is missing from the bag, your order is the record of what shipped.

Take it with you

Point a phone camera at the code and this page opens there. It is the same address as the one printed on your box, so it is also what to show someone you are passing the board to.