Abstract: A lighting system has an array (100) of at least one light-emitting solid-state element such as a light-emitting diode (LED) or a laser diode. A voltage source (10), which may supply either alternating or direct current, energizes the array. Array state circuitry (125; Q2, R2), electrically connected in series with the array (100), senses at least one state of the array, such as the amount of current passing through the array, or temperature. Secondary circuitry (127; R1, Q1; 200, 201, 202; 200, R4, Q1; 126, 127) is connected in parallel with the array (100). A switching component (Q1; Q1, Q3; 202) adjusts the current passing through the secondary circuitry in accordance with the sensed state of the array such that current through the array is maintained substantially constant.

Abstract: A printer circuit board for mounting electrical components such as LEDs has outward edge protrusion on which an electrically conductive material is deposited such that the board itself can be used to make electrical contact in a pre-existing, commercially available fitting, such as a screw-in or base fitting designed to receive incandescent light bulbs. For a screw-in fitting the board can optionally be made slightly wider than the inner diameter of the fitting but be provided with at least one axially extending slit; the board is then compressed slightly but biased outward to provide better electrical contact when inserted into fitting.

Abstract: At least one pair of LEDs, preferably of the super-luminescent type, are connected in parallel but with reverse polarity in series with at least one resistor and driven by a voltage source, which may deliver unrectified alternating current. An array of m series-connected LED pairs may be included in n parallel paths. The printed circuit board in which the LED pair(s) is mounted is adapted to fit into after-market fittings originally intended to receive incandescent light bulbs. In some embodiments, contacts are formed in the edges of lateral protrusions in the PCB.