Lighting device, comprising: - at least one LED (1a, 1b), - an adjustable electrical power supply (3a, 3b) for driving the LED (1a, 1b) in an active mode, by providing a forward driving voltage to the LED (1a, 1b), - a control device that comprises: - a measuring means (7, 9) having a measurement voltage source and a current meter, the measuring means (7, 9) being constructed to determine a value of an electric current through said LED (1a, 1b) at a predetermined measuring voltage across said LED (1a, 1b) when the LED (1a, 1b) is connected to the measuring means (7, 9), said current being indicative of an electrical resistance of said LED (1a, 1b), - a switch (5a, 5b) for selectively connecting said LED (1a, 1b) to said measuring means (7, 9) or to the adjustable power supply (3a, 3b), - a power supply control means connected the current meter and to the electrical power supply (3a, 3b) and constructed to provide a control signal to the adjustable electrical power supply (3a, 3b) for driving the LED (1a, 1b), and - an information retrieval means, connected to the power supply control means, containing information on the control signal as a function of the determined value of the current through said LED (1a, 1b), wherein - the power supply control means is constructed to retrieve the control signal from the information retrieval means on basis of the determined current, - the measurement voltage source is non-adjustable, of a higher precision than the adjustable electrical power supply (3a, 3b), and constructed for providing power to the LED (1a, 1b) when the LED (1a, 1b) is connected to the measuring means (7, 9), by supplying the predetermined measuring voltage to the LED (1a, 1b), - said predetermined measuring voltage is a voltage in a forward direction that is smaller than the forward driving voltage of said LED (1a, 1b) and that causes a current through said LED (1a, 1b) which is less than half of a lowest driving current provided to said LED (1a, 1b) by the adjustable electrical power supply (3a, 3b) in the active mode. - at least one LED (1a, 1b), - an adjustable electrical power supply (3a, 3b) for driving the LED (1a, 1b) in an active mode, by providing a forward driving voltage to the LED (1a, 1b), - a control device that comprises: - a measuring means (7, 9) having a measurement voltage source and a current meter, the measuring means (7, 9) being constructed to determine a value of an electric current through said LED (1a, 1b) at a predetermined measuring voltage across said LED (1a, 1b) when the LED (1a, 1b) is connected to the measuring means (7, 9), said current being indicative of an electrical resistance of said LED (1a, 1b), - a switch (5a, 5b) for selectively connecting said LED (1a, 1b) to said measuring means (7, 9) or to the adjustable power supply (3a, 3b), - a power supply control means connected the current meter and to the electrical power supply (3a, 3b) and constructed to provide a control signal to the adjustable electrical power supply (3a, 3b) for driving the LED (1a, 1b), and - an information retrieval means, connected to the power supply control means, containing information on the control signal as a function of the determined value of the current through said LED (1a, 1b), - a measuring means (7, 9) having a measurement voltage source and a current meter, the measuring means (7, 9) being constructed to determine a value of an electric current through said LED (1a, 1b) at a predetermined measuring voltage across said LED (1a, 1b) when the LED (1a, 1b) is connected to the measuring means (7, 9), said current being indicative of an electrical resistance of said LED (1a, 1b), - a switch (5a, 5b) for selectively connecting said LED (1a, 1b) to said measuring means (7, 9) or to the adjustable power supply (3a, 3b), - a power supply control means connected the current meter and to the electrical power supply (3a, 3b) and constructed to provide a control signal to the adjustable electrical power supply (3a, 3b) for driving the LED (1a, 1b), and - an information retrieval means, connected to the power supply control means, containing information on the control signal as a function of the determined value of the current through said LED (1a, 1b), - the power supply control means is constructed to retrieve the control signal from the information retrieval means on basis of the determined current, - the measurement voltage source is non-adjustable, of a higher precision than the adjustable electrical power supply (3a, 3b), and constructed for providing power to the LED (1a, 1b) when the LED (1a, 1b) is connected to the measuring means (7, 9), by supplying the predetermined measuring voltage to the LED (1a, 1b), - said predetermined measuring voltage is a voltage in a forward direction that is smaller than the forward driving voltage of said LED (1a, 1b) and that causes a current through said LED (1a, 1b) which is less than half of a lowest driving current provided to said LED (1a, 1b) by the adjustable electrical power supply (3a, 3b) in the active mode.