LED lamps and other performance parameters of the measurement
1, LED lighting electrical parameters of the measurement
Electrical parameters, including forward, reverse voltage and reverse current, related to the normal operation of LED lamps, LED lamps are to determine the basic performance of one of the basis. LED lamps have two kinds of electrical parameters measurement: the current is certain circumstances, the test voltage parameters; voltage must be the case, the test current parameters. The specific method is as follows:
(1) Forward voltage. The positive current is applied to the LED lamp to be detected, and a voltage drop is generated at both ends. Adjust the current value to determine the power supply, record the DC voltmeter on the relevant readings, that is, LED lamps forward voltage. According to the relevant common sense, LED positive conduction, the resistance is small, the use of ammeter external method more accurate.
(2) Reverse current. To the detection of LED lamps to apply reverse voltage, adjust the power supply, ammeter reading is the measured LED lamp reverse current. And measure the positive voltage with the same reason, because the LED reverse conduction resistance when the larger, using ammeter internal connection.
2, LED lamp thermal properties test
LED thermal properties, the LED optical properties, electrical characteristics have an important impact. Thermal resistance and junction temperature, is the main thermal properties of LED2. Thermal resistance refers to the thermal resistance between the PN junction and the surface of the shell, ie the ratio of the temperature difference along the heat flow path to the power dissipated on the channel. The junction temperature is the temperature of the PN junction of the LED.
Measuring LED junction temperature and thermal resistance methods are: infrared micro-instrument method, spectroscopy, electrical parameters, thermal resistance scanning method. Using infrared thermometer or micro-thermocouple measured LED chip surface temperature as LED junction temperature, accuracy is not enough.
At present, the commonly used electrical parameter method is the linear relationship between the forward voltage drop of the LEDPN junction and the PN junction temperature. The junction temperature of the LED is measured by measuring the forward voltage drop at different temperatures.