The pointer multimeter is mainly composed of a meter head, a measuring circuit component and a changeover switch. Its shape is portable and pocket-sized. The dial, the changeover switch, the zeroing knob, the test jack, etc. are mounted on the panel. The functions of various multimeters are slightly different, but the most basic functions are four: one is to test the DC current; the other is to test the DC voltage. The third is to test the AC voltage; the fourth is to test the DC resistance. Some multimeters can measure the audio level, AC current, capacitance, inductance, and p-value of the transistor. Due to these functions, the layout of the multimeter is also different.
In order to measure a variety of powers with a multimeter, and there are multiple ranges, it is necessary to convert the measured quantity into a DC current acceptable to the magneto-electric meter by the exchange of the measuring circuit. The more functions a multimeter has, the more complex its measurement circuitry. There are many resistors in the measurement circuit for testing current, voltage, and the like. The measuring circuit for testing the AC voltage further includes a rectifying device, and a dry battery should be used as a power source in the measuring circuit for testing the DC resistance.
The pointer multimeter's transfer switch is used to select different measured and different range switching devices. It contains a number of fixed and active contacts that can be turned on when the fixed and movable contacts are closed. Where fixed contacts are commonly referred to as "throws" and active contacts are commonly referred to as "knifes." When the switch is rotated, the knives are closed with different throws to form different measuring circuits. In addition, the knives and throws of the various transfer switches vary with the structure. The multimeter commonly used four-pole three-throw, single-pole nine-throw, double-knife and eleven throw.
The variety and structure of the multimeter is varied. When using, only the correct method can be used to ensure the accuracy of the test results, in order to ensure the safety of people and equipment.
(1) Use of jack and transfer switch Firstly, select the position of the jack or transfer switch according to the test items. Since the measurement voltage, current and resistance are alternately used during use, be sure not to forget the shift. It is not possible to measure the voltage by measuring the current or measuring the resistance. If you use a DC current or a resistance file to misinterpret the AC 220V power supply, the multimeter will burn out immediately.
(2) The use of test pens The multimeter has two red and black test pens. Don't look at it. It can be used freely. It is also very knowledgeable. If the position is reversed or wrong, it will bring a test error. Or the danger of burning the meter. Generally, the red pen of the multimeter is "+" and the black pen is "one". When inserting the meter into the multimeter jack, be sure to press the color and positive and negative. When measuring DC voltage or DC current, be sure to pay attention to the positive and negative polarity. When measuring current, the test leads are connected in series with the circuit. When measuring voltage, the test leads are connected in parallel with the circuit, so you can't make a mistake. In the process of measuring voltage or current, the switch is also switched.
3) How to correctly read the multimeter Before using the multimeter, check if the pointer is at the zero position. If you do not refer to the zero position, you can adjust the mechanical zero adjuster on the cover to zero.
If the multimeter has multiple rulers, be sure to recognize the corresponding reading scale. You can't save the AC and DC scales arbitrarily, and you can't misread them.
The multimeter has multiple ranges for the same measurement item. For example, the DC voltage range is 1 volt, 10 volts, 25 volts, 100 volts, 500 volts, etc., and the range selection should move the pointer to 2/3 of the full scale. When measuring the resistance, the pointer should be pointed near the center resistance of the file to make the measurement accurate.
2. Operation (1) Measurement of resistance Take different resistances and potentiometers and measure with a pointer multimeter. The steps are as follows:
When measuring the resistance of the multimeter, first connect the two test leads shortly, and turn the zero adjustment potentiometer to zero, so that the pointer points to the ohmic zero position. And the zero potentiometer must be re-adjusted after each shift.
When selecting the ohmic gear position, try to select the position where the measured resistance value is close to the center resistance reading of the dial to improve the accuracy of the test results. If the measured resistance is on the circuit board, it should be soldered to one end for testing. Otherwise, the measured resistance has other components shunted and the reading is not accurate. When measuring the high resistance value, do not touch the surface and the resistance lead respectively with the fingers of both hands to prevent the human body from shunting and increase the error. Resistances with less stringent resistance requirements are acceptable within ±20% of the resistance. At the same time, it should be noted that the multimeter itself generally has an error of ±2.5%. Special care should be taken during measurement to not measure the resistor under live conditions.
When measuring the potentiometer with a multimeter, first measure the two soldering pieces of the potentiometer with red and black test leads, and the resistance should be the same as the nominal value. Then connect the test leads to the center tap and any end of the potentiometer, and rotate the potentiometer shaft handle (such as the linear potentiometer movable sliding arm). If the needle changes slowly without falling, the resistance value changes continuously and smoothly. normal. If the resistance changes unevenly, it may be that the rotor is in poor contact. If the resistance is abrupt or the minimum resistance is not small enough and the maximum resistance is not large enough (not reaching the nominal value), it may be partial damage to the carbon film.
2 use of the multimeter (2) measuring the resistance value to the ground, the so-called grounding resistance, that is, using the multimeter red test pen grounding, the black test pen to measure the point of the circuit under test (such as components, integrated circuit pins, etc.) in the road resistance The value is compared with the normal measured resistance value to determine the fault range.
When measuring, take a mobile phone circuit board, set the resistance gear position in RxlK file, measure the resistance value of a certain point on the mobile phone circuit board, and compare with normal to see if it is the same.
If the measurement difference is large, it indicates that there is a fault in this part of the circuit. Such as filter capacitor leakage, open circuit or integrated circuit damage.
(3) Measurement of crystal diode By measuring the forward and reverse resistance of the diode, it is possible to check the quality of the diode. The reverse resistance is generally required to be several hundred times larger than the forward resistance. That is to say, the smaller the forward resistance, the better, and the larger the reverse resistance, the better.
Take different specifications of the diode for measurement, as follows:
Rotate the multimeter's range to ohms x100 or xIK to measure the diode. Can not use X10 file, can not use x10K file. Because the former is too small, the current through the diode is too large, and the diode is easily burned. The latter is easy to break down the diode with low voltage due to the high internal voltage of the multimeter.
If the measured resistance is only a few hundred ohms to several thousand ohms (forward resistance), the test leads should be replaced and retested. The measured resistance should be several hundred kilohms (reverse resistance), indicating that Only diodes can be used. When measuring the forward resistance of a diode, the one measured by the red test lead is the negative pole of the diode, and the one measured by the black test lead is the positive pole of the diode.
(4) Measurement of DC voltage Adjust the multimeter to the DC voltage range and select the range pointer to 2/3 of the full scale deflection. If the voltage on the circuit is not estimated, use a large range first, and then use the appropriate range after rough measurement. This will prevent the multimeter from being damaged due to excessive voltage.
When measuring, connect the multimeter to the circuit under test in parallel. Touch the red meter on the multimeter to the positive end of the circuit under test, and touch the black pen to the negative side of the circuit. Do not reverse it. When measuring a relatively high voltage, you should pay special attention to the fact that both hands hold the red and black test leads respectively.
The edge portion is measured, or a table is first fixed at one end, and then another test pen is touched to the tested point.
(5) Measurement of AC and DC voltage The measured AC voltage is the same as the measured DC voltage. Just adjust the multimeter to the AC position.
3. Handling Precautions (1) Before using the multimeter, be familiar with the various switches, knobs or buttons. Dedicated sockets, measuring jacks and the corresponding accessories, to understand the measured power corresponding to each tick mark. When picking up the test leads for the first time, be sure to check that the type of measurement and the range selection switch are dialed, otherwise the multimeter may be damaged.
(2) When the multimeter is used, it should be placed horizontally, dry, vibration-free, and free of strong magnetic fields. Use under ambient conditions.
(3) After the measurement is completed, the range selection switch should be set to the highest voltage level to prevent the multimeter from being burnt out at the beginning of the next time.
Cosmetic Instrument Vibration Motor
Cosmetic Instrument Vibration Motor Mainly used in cosmetic instrument, such as instrument, cleansing essence introducing vibration meter, wash a face, facial massage, hairdressing instrument, etc.
Operating temperature range:
Cosmetic Instrument Vibration Motor should be used at a temperature of -10~60℃.
The figures stated in the catalog specifications are based on use at ordinary room temperature catalog specifications re based on use at ordinary room temperature (approximately20~25℃.
If a Cosmetic Instrument Vibration Motoris used outside the prescribed temperature range,the grease on the gearhead area will become unable to function normally and the motor will become unable to start.Depending on the temperature conditions ,it may be possible to deal with them by changing the grease of the motor's parts.Please feel free to consult with us about this.
Storage temperature range:
Cosmetic Instrument Vibration Motor should be stored ta a temperature of -15~65℃.
In case of storage outside this range,the grease on the gearhead area will become unable to function normally and the motor will become unable to start.
Service life:
â—Use with a load that exceeds the rated torque
â—Frequent starting
â—Momentary reversals of turning direction
â—Impact loads
â—Long-term continuous operation
â—Forced turning using the output shaft
â—Use in which the permitted overhang load or the permitted thrust load is exceeded
â—A pulse drive ,e.g.,a short break,counter electromotive force,PWM control
â—Use of a voltage that is nonstandard as regards the rated voltage
â—Use outside the prescribed temperature or relative-humidity range,or in a special environment.
â—Please consult with us about these or any other conditions of use that may apply,so that we can be sure that you select the most appropriate model.
when it come to volume production,we're a major player as well .each month,we rurn out 600000 units,all of which are compliant with the rohs directive.Have any questions or special needed, please contact us, we have the engineer group and best sales department to service to you Looking forward to your inquiry. Welcome to our factory.
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