Ten LEDs in one package

Twenty pins, ten circuits

The package is 25.4 mm long and 10.1 mm wide, with ten pins along each side at the usual 2.54 mm spacing. The two rows are 7.62 mm apart — 0.3 inches, the width of a narrow chip — so it sits across the channel in the middle of a breadboard with five free holes on each side of every pin.

Inside, there is nothing but ten LEDs. Pin 1 of the top row and pin 1 of the bottom row are the two ends of segment one, and so on down the bar. No common pin, no driver, no chip.

Which way round

One row is the anodes and the other is the cathodes, and nothing printed on the part tells you which. That sounds worse than it is, because of what happens when you guess wrong: an LED simply does not conduct backwards, so the whole supply sits across it, no current flows, and the bar stays dark. Nothing gets hot. Turn it round and try again.

The 220 Ω resistors on the board in the box are what make that safe. A bare LED straight across 5 V, the right way round, is a different story.

The frame

Each bar comes with a printed frame that it sits in. It is a surround rather than a case: it hides the edge of the package, keeps dust off the windows, and makes a lit bar read as a panel instead of a component. It does not change the pin spacing, so a framed bar still goes in a breadboard.

The model for it is in the kit's example download, so a frame that goes missing can be printed again.