What are the diode tests? — SUNMATE
What are the diode tests?
When the diode is tested with a multimeter, one end of the black probe connected with a smaller value is positive, and the other end of the red probe is negative. If the forward and reverse resistances are infinite, it indicates that the diode has been opened and damaged; If the forward and reverse resistance are both 0, it indicates that the diode has been short circuited and damaged. Under normal conditions, the forward resistance of germanium diode is about 1.6k Ω.
When using a digital multimeter to measure the diode, the red probe is connected to the positive pole of the diode, and the black probe is connected to the negative pole of the diode. At this time, the measured resistance is the positive conduction resistance of the diode, which is just the opposite of the pointer multimeter.
It is more convenient to use the diode block of the digital multimeter to detect the diode: place the digital multimeter in the diode block, connect the negative pole of the diode with the black probe of the digital multimeter, and connect the positive pole with the red probe. At this time, the display screen will display the positive voltage drop value of the diode. The forward voltage drop of diodes made of different materials is different: 0.55-0.7V for silicon diodes and 0.15-0.3V for germanium diodes. If the display screen shows "0000", it indicates that the pipe has been short circuited; If "0L" or "Overload" is displayed, it indicates that the diode is in open circuit or in reverse state. At this time, the probe can be exchanged for retesting.