How to distinguish the gear of the multimeter? Multimeter range changeover switch usage
The three basic functions of the multimeter are to measure resistance, voltage, and current, so the old-timers call it a three-purpose meter.
Many new functions have been added to the current multimeter, especially the digital multimeter, such as measuring capacitance value, transistor magnification, diode voltage drop, etc. There is also a talking digital multimeter that can broadcast the measurement results in language. There are also many classic models of digital multimeters
The following suffix indicates the difference in function. Among them, the multimeter has been bought for more than 30 yuan, which is cheap enough.
The biggest feature of the multimeter is that there is a range switch, and each function is switched by this switch. Basically, A- is used to represent the measured DC current, and there are generally several levels for the milliampere and ampere levels. V- means measuring DC voltage. Advanced multimeters have millivolt ranges, and voltage ranges are also divided into several ranges. V~ is used to measure AC voltage. A~ Measuring AC current.
Use the Ω ohm file to measure the resistance. For the pointer multimeter, you need to do a zero adjustment every time you change the resistance file. Zero adjustment is to put the red test lead and black test lead of the multimeter together.
together, and then turn the zero adjustment knob so that the pointer points to the zero position. hFE is used to measure 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 board, the hFE value can be measured. Note that PNP and NPN are different.
The following takes the MF30 multimeter as an example to illustrate the readings of the multimeter. The first scale line is the indication of the resistance value, the left end is infinity, the right end is zero, and the middle scale is uneven. The resistance files include R×1, R×10, R×100, R×1K, R×10K, respectively explaining the multiples to be multiplied by the indication of the scale to get the actual resistance value (in ohms).
For example, if you measure a resistance with R×100 gear, and the pointer indicates “10”, then its resistance value is 10×100=1000, which is 1K.
The second scale line is shared by the 500V range and the 500mA range. It should be noted that the indication principle of the voltage range and the current range is different from that of the resistance range. If the current exceeds the range, it will damage the multimeter.
The gear of the multimeter is to measure the conduction voltage drop of the diode, and it can also measure the continuity of the circuit.
How to use: Select this gear with the rotary switch, insert the test lead in the non-current position, touch the two pins of the diode or the circuit test point with the test lead, if the circuit is connected, the buzzer will sound, if the test is a diode, One direction will display about 0.7V, which is the forward voltage drop of the diode, and the other direction will display the overflow symbol, indicating non-conduction.
In addition, this gear can also measure light-emitting diodes.
