When detecting a light emitting diode with a multimeter, you must use the "R × l0k" file. We have already talked about the storm. Light-emitting diode voltage drop of 2V. The Meter is in "R × lk" and the following power-blocking. Inner battery is only 1.5V. Lower than the pressure drop, whether positive, negative access, light-emitting diodes can not turned on, it can not be detected. . R × 1k "slotting inner connected with 9V (or 15V) high-voltage battery, higher than the pressure drop, it can be used to detect the light emitting diode is detected. The two leads, respectively, and the two leads connecting the light emitting diode, such as hands deflection half, while the light emitting diode has a point out of light, a light- emitting diode is forward access, and then the black pen (connected to the battery positive electrode in the table) is in contact with the positive electrode; and red pen (with the inner battery negative attached) is in contact with the negative electrode.

then after two swap table pen contact with the light-emitting diode, then the reverse access, hands should not move. If the access regardless of the forward or reverse access, hands or head are deflected not moving, the light emitting diode is damaged.