What is the positive resistance of a normal diode when measured by a multimeter, and how large is the reverse?
Usually, the forward resistance of germanium material diode is about 1K, and the reverse resistance value is about 300. The resistance of silicon material diode is about 5 K ohms, and the reverse resistance value is infinity. Added: common light emitting diode detection, with Multimeter test. Using a pointer type multimeter with * 10K block, the quality of the LED can be roughly judged. Normally, the diode forward resistance is ten to 200K, reverse resistance to /.
Measurement method: (2) according to the diode's forward resistance is small, reverse resistance big characteristics, can determine the diode polarity. Dial the multimeter to the ohm gear (like R x 100 or R * 1K block, don't use R x 1 block or R * 10K block. Because the R x 1 block uses too much current, it is easy to burn the tube; and the R * 10K block uses too high a voltage to break through the tube. With a pen are respectively connected with the bipolar diode, measured two resistance in the measured resistance of a small, one end is connected with the black pen as the anode of the diode. Similarly, in the measured a large resistance, one end connected to the black pen for the negative electrode of the diode. If the measured reverse resistance is very small, it shows that the diode is internally short circuited; if the forward resistance is great, then the internal circuit is broken. In these two cases, the diode needs to be scrapped.
The positive and negative resistance of the diode varies according to the material. There are large and small, but generally speaking, the resistance value of the reverse resistor will be at 300K ~ infinity, while the forward resistance will be 100 times smaller than the reverse resistance.
