4. Working with LEDs

LED-equipped Hives offer green, yellow and red LEDs. Start with an LED example in Available circuits, or build your own supported circuit in a full Hive session. Demo access is limited to its listed circuits; its component library is a preview, not an editable breadboard.

4.1. Connecting an LED

The catalog examples use the positive DC supply, up to 5 V, and a separate 1 kΩ series resistor for each LED for better visibility. The existing 10 kΩ examples, including the restricted demo, remain supported. Do not bypass a resistor with a wire. Other combinations depend on the permitted circuits; the 100 Ω LED configuration is limited to 3 V.

The two terminals are different: cathode (K) and anode (A). The flat edge and dark band identify the cathode. In the examples, the cathode goes to ground and the anode connects to the resistor. Rotating the component also rotates its terminal positions. The accessible component name identifies the cathode and anode holes and the rotation.

The compact LED spans three hole intervals. Place each lead in a separate physical hole; electrically connected holes are not the same physical hole. Amber placement markers and accompanying text identify shared holes or leads that are not in a hole. They are advisory: you may still keep components in the tray or move them aside while working. A lead outside a hole means that component is not included in the requested circuit.

You can use one LED of each available colour, including two or three independent branches together. Every LED needs its own resistor. Availability depends on the Hives accessible to your institution and their permitted circuits. A component shown in the picker does not guarantee that every circuit containing it can be built. If a request cannot be built, check the connections, component values and available hardware.

4.2. Estimated glow and real measurements

Estimated glow is on by default and illustrates the last successful measurement on the breadboard. You can turn it off using the checkbox. Open How this works for the estimated current for each LED and the explanation of its source.

This is not measured brightness or a live camera view. Only recognized simple DC branches with a supported resistor are estimated. Some estimates use a relevant voltage or branch-current reading; others use nominal component values. The model is not calibrated to your individual LED, and different colours must not be compared as a brightness scale. An earlier recording or simulation is labelled accordingly.

Changing the circuit or instrument settings clears the old illustration. Make another measurement to update it. Unsupported circuits, missing readings or unconnected LEDs show Estimate unavailable, not a guessed brightness. Very small positive currents can be shown numerically even when no glow is drawn.

For a more direct branch-current calculation, measure the voltage across that LED’s resistor and use I = V / R (volts, ohms and amperes): divide by 1,000 for 1 kΩ or by 10,000 for 10 kΩ. This still depends on resistor tolerance and is not an optical measurement. Camera snapshots show the real rack, but exposure and neighbouring lights can mask brightness changes. Compare estimates only for the same LED, and use measurements for quantitative conclusions.

4.3. Saving and examples

New saves preserve the compact LED footprint. Older saved circuits retain their original LED spacing. Use a freshly loaded Hive page when opening the new examples.

See the LED circuit catalog for diagrams and downloadable examples.