First, carry out mechanical zero adjustment.
Second, choose the appropriate range gear.
3. When measuring the current using the multimeter current block, the multimeter should be connected in series to the subtest circuit, because only the series connection can make the current flowing through the ammeter the same as the current of the measured branch. When measuring, disconnect the measured branch and connect the multimeter red and black test leads between the two points that are disconnected. In particular, it should be noted that the ammeter cannot be connected to the sub-test circuit. This is very dangerous and it is easy to burn the meter.
Fourth, pay attention to the polarity of the measured power.
5. Correct use of scales and readings.
6. When selecting a 2.5A block with DC current, the multimeter red test pen should be inserted in the 2.5A measurement jack, and the range switch can be placed on any range of the DC current block.
7. If the DC current measured by the submeter is greater than 2.5A, the 2.5A gear can be expanded to 5A gear. The method is very simple, the user can connect a 0.24 ohm resistor between the "2.5A" jack and the black test lead jack, so that the gear becomes a 5A current block. The 0.24A resistor connected should be selected with a wirewound resistor of 2W or more. If the power is too small, it will burn out.
The current multimeters are divided into pointers and digital ones. They have their own conveniences. It is hard to say who is good or who is bad. It is better to have one for each pointer and digital. Amateur electronics can have a pointer-type MF30 multimeter, which is a classic model. There is also a veteran MF500 multimeter, a cheap MF50 multimeter, which can generally be bought at a telecommunications store.
The three basic functions of the multimeter are to measure resistance, voltage, and current, so the older generation called it a three-meter. Today's multimeters add a lot of new features, especially digital multimeters, such as measuring capacitance values, triode amplification, diode drop, etc., and a talking digital multimeter that can broadcast the measurement results in language. (In fact, it is not very difficult, Bitbaby once wanted to use MCU and voice circuit to do one :-)
Digital multimeters also have many classic models, such as DT830C, DT830C, DT890D, etc. The suffixes on the back indicate functional differences, of which DT830C has bought more than 30 yuan, which is cheap enough. Bitbaby has installed a MF50 multimeter in school. The circuit principle is not complicated. It is just that so many components are not fixed by the printed board, but directly soldered to the wiring board. It is still a little trouble for beginners.
The biggest feature of the multimeter is that it has a range switch, and each function is switched by this switch. Basically, A- is used to indicate the DC current. Generally, the milliamp and the amper are divided into several files. V- indicates the DC voltage measurement. The multimeter of the advanced point has a millivolt file, and the voltage file is also divided into several files. V~ is used to measure the AC voltage. A~ Measure AC current.
Ω ohm test resistance, for the pointer multimeter, each time you change the resistance file, you need to do a zero adjustment. Zeroing is to put the multimeter's red and black pens together, then turn the zero button to point the pointer to zero. hFE is the current amplification factor of the triode. As long as the three pins of the triode are inserted into the corresponding holes on the universal surface plate, the hFE value can be measured. Note that PNP and NPN are different.
The following uses the MF30 multimeter as an example to illustrate the reading of the multimeter. The first tick mark is the resistance value indication, the leftmost end is infinity, the right end is zero, and the scale is uneven. The resistance file has R×1, R×10, R×100, R×1K, and R×10K, which respectively indicate the multiplication of the indication of the scale, and then the actual resistance value (in ohms) is obtained.
For example, if a resistance is measured by R×100, and the pointer is indicated as “10â€, then its resistance value is 10×100=1000, that is, 1K. The second tick mark is shared between the 500V gear and the 500mA gear. It should be noted that the indication principle of the voltage gear and the current gear is different from the resistance gear. For example, the 5V gear indicates that the gear can only measure the voltage below 5V, and the 500mA gear can only measure 500mA. The following currents, if they exceed the range, can damage the multimeter.
Note: The multimeter should be placed horizontally when in use. The red test pen is inserted in the + hole, and the black test pen is inserted into the hole. The test current uses the current file, but the voltage file and the electric block cannot be misused. Others are the same. Otherwise, the fuse in the multimeter is burned, and the meter is damaged. If you don't know the range beforehand, try to measure with the maximum range, then disconnect the measurement circuit and then shift the gear, and cut the range without being online. In the case where the hands are quickly deflected to the end, the circuit should be disconnected immediately for inspection.
Finally, there is a rule that the multimeter after the appointment is used to set the range switch to the highest level of the AC voltage, in case someone else accidentally measures the 220V mains voltage and is damaged. Remember the fine traditions of this old generation!
Second, choose the appropriate range gear.
3. When measuring the current using the multimeter current block, the multimeter should be connected in series to the subtest circuit, because only the series connection can make the current flowing through the ammeter the same as the current of the measured branch. When measuring, disconnect the measured branch and connect the multimeter red and black test leads between the two points that are disconnected. In particular, it should be noted that the ammeter cannot be connected to the sub-test circuit. This is very dangerous and it is easy to burn the meter.
Fourth, pay attention to the polarity of the measured power.
5. Correct use of scales and readings.
6. When selecting a 2.5A block with DC current, the multimeter red test pen should be inserted in the 2.5A measurement jack, and the range switch can be placed on any range of the DC current block.
7. If the DC current measured by the submeter is greater than 2.5A, the 2.5A gear can be expanded to 5A gear. The method is very simple, the user can connect a 0.24 ohm resistor between the "2.5A" jack and the black test lead jack, so that the gear becomes a 5A current block. The 0.24A resistor connected should be selected with a wirewound resistor of 2W or more. If the power is too small, it will burn out.
The current multimeters are divided into pointers and digital ones. They have their own conveniences. It is hard to say who is good or who is bad. It is better to have one for each pointer and digital. Amateur electronics can have a pointer-type MF30 multimeter, which is a classic model. There is also a veteran MF500 multimeter, a cheap MF50 multimeter, which can generally be bought at a telecommunications store.
The three basic functions of the multimeter are to measure resistance, voltage, and current, so the older generation called it a three-meter. Today's multimeters add a lot of new features, especially digital multimeters, such as measuring capacitance values, triode amplification, diode drop, etc., and a talking digital multimeter that can broadcast the measurement results in language. (In fact, it is not very difficult, Bitbaby once wanted to use MCU and voice circuit to do one :-)
Digital multimeters also have many classic models, such as DT830C, DT830C, DT890D, etc. The suffixes on the back indicate functional differences, of which DT830C has bought more than 30 yuan, which is cheap enough. Bitbaby has installed a MF50 multimeter in school. The circuit principle is not complicated. It is just that so many components are not fixed by the printed board, but directly soldered to the wiring board. It is still a little trouble for beginners.
The biggest feature of the multimeter is that it has a range switch, and each function is switched by this switch. Basically, A- is used to indicate the DC current. Generally, the milliamp and the amper are divided into several files. V- indicates the DC voltage measurement. The multimeter of the advanced point has a millivolt file, and the voltage file is also divided into several files. V~ is used to measure the AC voltage. A~ Measure AC current.
Ω ohm test resistance, for the pointer multimeter, each time you change the resistance file, you need to do a zero adjustment. Zeroing is to put the multimeter's red and black pens together, then turn the zero button to point the pointer to zero. hFE is the current amplification factor of the triode. As long as the three pins of the triode are inserted into the corresponding holes on the universal surface plate, the hFE value can be measured. Note that PNP and NPN are different.
The following uses the MF30 multimeter as an example to illustrate the reading of the multimeter. The first tick mark is the resistance value indication, the leftmost end is infinity, the right end is zero, and the scale is uneven. The resistance file has R×1, R×10, R×100, R×1K, and R×10K, which respectively indicate the multiplication of the indication of the scale, and then the actual resistance value (in ohms) is obtained.
For example, if a resistance is measured by R×100, and the pointer is indicated as “10â€, then its resistance value is 10×100=1000, that is, 1K. The second tick mark is shared between the 500V gear and the 500mA gear. It should be noted that the indication principle of the voltage gear and the current gear is different from the resistance gear. For example, the 5V gear indicates that the gear can only measure the voltage below 5V, and the 500mA gear can only measure 500mA. The following currents, if they exceed the range, can damage the multimeter.
Note: The multimeter should be placed horizontally when in use. The red test pen is inserted in the + hole, and the black test pen is inserted into the hole. The test current uses the current file, but the voltage file and the electric block cannot be misused. Others are the same. Otherwise, the fuse in the multimeter is burned, and the meter is damaged. If you don't know the range beforehand, try to measure with the maximum range, then disconnect the measurement circuit and then shift the gear, and cut the range without being online. In the case where the hands are quickly deflected to the end, the circuit should be disconnected immediately for inspection.
Finally, there is a rule that the multimeter after the appointment is used to set the range switch to the highest level of the AC voltage, in case someone else accidentally measures the 220V mains voltage and is damaged. Remember the fine traditions of this old generation!
Lubrication System,Lube Oil System,Dry Sump Lubrication System,Engine Lubrication System
Chongqing LDJM Engine Parts Center , https://www.ckcummins.com