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We present an electrical model for quantum-well light-emitting diodes (LEDs) with a current-spreading layer. The LEDs studied have a multiquantum well (MQW) between p-GaN and the n-GaN grown on sapphire. The model consists of a diode connected with a series resistor resulting from the combined resistance of the p-n junction, contacts, and current spreader. Based upon this model, the I-V curve of the diode itself without the series resistance is extracted from the measured LED I-V curve. The model also includes an empirical diode current equation which was sought by matching the extracted I-V curve. In the seeking process, junction temperature (Tj) rather than case temperature (Tc) was used in the equation. The diode model allows one to calculate the reduction on conversion efficiency caused by the series resistor. Results show that the current-spreading layer causes 20% of the efficiency reduction at Tj=107°C.