Patent ID: 8016440

Claim:
A method of making an interchangeable LED bulb that can be interchangeably used with other LED bulbs in an LED light string without affecting performance and luminosity of said light string, said LED bulb having a first resistor, a second resistor, and an LED element, comprising: selecting an operating current (I LED ) and an operating voltage (V LED ) for said LED element of said interchangeable LED bulb, to create a substantially predetermined luminosity of said LED element, said substantially predetermined luminosity of said LED element being substantially similar to a luminosity of other LED elements of said other LED bulbs; selecting a standardized input impedance for said interchangeable LED bulb that is substantially equal to input impedances of said other LED bulbs in said LED light string, by determining an input voltage and an input current to be applied to said interchangeable LED bulb when said interchangeable LED bulb is inserted in said light string; selecting resistive values for said first resistor and said second resistor so that said operating current (I LED ) flows through, and said operating voltage (V LED ) is applied across, said LED element to create said substantially predetermined luminosity of said LED element, and said interchangeable LED bulb has an input impedance that is substantially equal to said standardized input impedance so that the luminosity of said other LED bulbs on said LED light string does not substantially change when said interchangeable LED bulb is inserted in said LED light string; connecting a first resistor in series with said LED element; connecting a second resistor in series with said first resistor and in parallel with said LED element.