1. The problem statement, all variables and given/known data Depending on which substances they're composed, light emitting diodes typically need 1.5 - 3 V in forward bias to give satisfactory light. You have two light emitting diodes, red and orange, you want to couple together in a capsule. You want to make a circuit where the capsule sends out red or orange light, or a mixture of these two. That is so that one or the other or both diodes send out light. Draw ciruits with the diodes and a proper power supply. 2. Relevant equations N/A. That is I must use Kirchoffs 2. law for the voltages, right? 3. The attempt at a solution I don't know exactly how to solve this. The diodes need 1.5 - 3 V voltage. To make the different combinations (diode 1 sends out red light, diode 2 sends out orange light, or they both combine to give a red-orange light) I must vary series and parallell coupling right? Or shall all combinations be possible in the same circuit? How shall these circuits be? Could anybody give me some help here?