The method of measuring diode with digital multimeter diode file
Use the diode gear of the digital multimeter to measure the forward and reverse resistance (voltage drop) of the diode to quickly judge the quality of various diodes. The specific measurement method is introduced below.
When measuring the quality of a diode, first adjust the range switch of the digital multimeter to the diode position, and then touch the positive and negative poles of the diode with red and black test leads (generally, the pin with the color ring on the diode shell is the negative pole). For good silicon diodes, the readings displayed by the multimeter are generally in the range of 0.500 to 0.700 (the specific size is related to the type of diode and the test current of the multimeter); for good Schottky diodes and germanium diodes, the readings displayed by the multimeter are generally in the 0.150～0.300. The figure above shows the readings displayed by a multimeter measuring a good silicon rectifier diode.
When measuring the forward resistance of a diode, if the reading displayed by the multimeter is "0.00" or "OL (overflow)", it means that the diode is damaged.
After measuring the forward resistance of the diode, exchange the red and black test leads, touch the negative electrode of the diode with the red test lead, and touch the positive electrode of the diode with the black test lead, as shown in the figure above. At this time, for good diodes, the readings displayed by the multimeter are generally "OL".
When measuring the forward and reverse resistance of a diode with a multimeter, if the forward and reverse readings displayed by a certain diode are both "0.00" or "OL", it means that the diode is damaged.
How to measure voltage with a multimeter? How to measure voltage with a multimeter
The method of measuring voltage is simpler and safer than the method of current, because the original circuit does not need to be changed when measuring resistance, just connect the multimeter pen to both ends of the component under test. There will be no short circuit, the current range is different, and the internal resistance is almost zero. If the connection is wrong, the remaining components may be burned.
Determine the type of power supply under test
Before measuring the voltage at both ends of the component, first judge the voltage type, whether it is AC voltage or DC voltage. The multimeter for AC and DC is not in the same gear, so judge the type before measuring. Use the DC gear for DC and use the AC gear for AC. bit.
After judging, choose the appropriate range. If you don’t know the voltage to be measured, you can choose the largest range and change the range according to the displayed voltage.
measuring voltage
After the preparatory work of the first two steps is completed, then you can put the test leads at both ends of the power supply to be tested. If the measurement is correct, the voltage at this time will be displayed on the display of the multimeter.
