Valgusdiood ehk leed on p-n-siiret sisaldav tahkisseadis, mis ergastamisel elektrivooluga emiteerib optilist kiirgust ja mille kiirgusspektri põhiline osa asub spektri nähtavas alas.
A light-emitting diode, or LED, is a solid-state device containing a p-n junction that emits optical radiation when excited by an electric current, with the main part of its emission spectrum lying within the visible range.
