Commonly used electrical instruments
First, the multimeter
The multimeter is also called multi-meter and three-meter. It is a multi-function, multi-range measuring instrument. The general multimeter can measure DC current, DC voltage, AC voltage, resistance and audio level, etc. Some can also measure AC current and electricity. Capacity, inductance and some parameters of the semiconductor.
1. How to use the mechanical multimeter
(1) Familiarize with the meaning of the symbols on the dial and the main functions of each knob and selector switch.
(2) Perform mechanical zero adjustment.
(3) According to the type and size of the measurement, select the gear and range of the transfer switch to find the corresponding tick mark.
(4) Select the position of the test lead jack.
(5) Measurement voltage: When measuring voltage (or current), select a good range. If you use a small range to measure large voltage, there is a danger of burning the watch. If you use a large amount of process to measure small voltage, the pointer deflection is too small. Unable to read. The range should be chosen to deflect the pointer to about 2/3 of the full scale. If you do not know the magnitude of the voltage to be measured beforehand, you should first select the highest range and then gradually reduce it to the appropriate range.
a Measurement of AC voltage: Place one switch of the multimeter in AC and DC voltage, and the other switch is placed on the appropriate range of AC voltage. The multimeter's two test leads and the circuit under test or load can be connected in parallel.
b DC voltage measurement: put one switch of the multimeter in the AC and DC voltage, the other switch is placed on the appropriate range of DC voltage, and the “+†meter (red pen) is connected to the high potential, “- The test pen (black pen) is connected to the low potential, that is, the current flows from the "+" test pen and flows out from the "-" test pen. If the test leads are reversed, the pointer of the watch will deflect in the opposite direction, which is easy to bend the pointer.
(6) Measuring current: When measuring DC current, put one switch of the multimeter in the DC current block, and the other switch is placed on the appropriate range of 50uA to 500mA. The range selection and reading method of the current is the same as the voltage. The circuit must be disconnected first, and then the multimeter is connected in series to the circuit under test according to the current from "+" to "-", that is, the current flows from the red meter pen and flows out from the black meter pen. If the multimeter is connected in parallel with the load, the internal resistance of the meter head is small, which may cause the short circuit to burn the instrument.
(7) Measuring resistance: When measuring resistance with a multimeter, it should be operated as follows:
a Select the appropriate override. The scale of the multimeter's ohmic gear is not uniform, so the selection of the override gear should be such that the pointer stays in the thinner part of the scale, and the closer the pointer is to the middle of the scale, the more accurate the reading. Under normal circumstances, the pointer should be pointed between 1/3~2/3 of the scale.
b ohms zero. Before measuring the resistance, short the two test leads and adjust the “ohmic (electrical) zero adjustment knob†so that the pointer just points to the zero position to the right of the ohmic scale. If the pointer cannot be adjusted to zero, the battery voltage is insufficient or
There is a problem inside the meter. And every time you change the override gear, you must perform ohms zero again to ensure accurate measurement.
c Reading: The reading of the meter is multiplied by the magnification, which is the resistance of the measured resistance.
(8) Precautions
a When measuring current and voltage, it is not possible to charge range
b When selecting the range, first select the big one, then select the small one, try to make the measured value close to the range.
c When measuring resistance, it is not possible to measure with electricity. Because the multimeter is powered by the internal battery when measuring resistance, if the live measurement is equivalent to accessing an additional power supply, the meter may be damaged.
d After use, the switch should be in the maximum gear or neutral of the AC voltage.
2, the use of digital multimeter
Nowadays, digital measuring instruments have become the mainstream, and there is a trend to replace analog meters. Compared with analog instruments, digital meters have high sensitivity, high accuracy, clear display, strong overload capability, easy to carry, and simpler to use.
(1) Before use, you should carefully read the relevant instruction manual and be familiar with the functions of the power switch, range switch, jack, and special socket.
(2) Set the power switch to the ON position.
(3) Measurement of AC and DC voltage: If necessary, set the range switch to the appropriate range of DCV (DC) or ACV (AC), insert the red test pen into the V/Ω hole, insert the black test lead into the COM hole, and connect the test lead to the line under test. Parallel, the reading is displayed.
(4) Measurement of AC and DC current: Turn the range switch to the appropriate range of DCA (DC) or ACA (AC), insert the red test lead into the mA hole (<200mA) or 10A hole (>200mA), and insert the black test lead into the COM. Hole and connect the multimeter in
It can be used in the circuit under test. When measuring DC, the digital multimeter can automatically display the polarity.
(5) Measurement of resistance: Turn the range switch to the appropriate range of Ω, insert the red test lead into the V/Ω hole, and insert the black test lead into the COM hole. If the measured resistance value exceeds the maximum value of the selected range, the multimeter will display "1", then you should select a higher one.
Range. When measuring resistance, the red test pen is positive and the black test pen is negative, which is the opposite of the pointer multimeter. Therefore, when measuring polar components such as transistors and electrolytic capacitors, you must pay attention to the polarity of the test leads.
(6). Precautions for use
a If you cannot estimate the magnitude of the measured voltage or current in advance, you should first dial the measurement to the highest range and then gradually reduce the range to the appropriate position. After the measurement is completed, the range switch should be turned to the highest voltage and the power should be turned off.
b When the scale is full, the meter only displays the number “1†in the highest position, and the other bits disappear. In this case, a higher range should be selected.
c When measuring voltage, the digital multimeter should be connected in parallel with the circuit under test. When measuring current, it should be connected in series with the circuit under test. It is not necessary to consider positive and negative polarity when measuring DC.
d When the AC voltage is misused to measure the DC voltage, or the DC voltage is used to measure the AC voltage, the display will show “000â€, or the number on the low position will jump.
e It is forbidden to change the range when measuring high voltage (above 220V) or high current (above 0.5A) to prevent arcing and burn switch contacts.
How to judge the quality and polarity of ordinary three tubes with a multimeter
1. Determine the tube type and base. When measuring, first place the multimeter in the “R×100†or “R×1K†file, then assume that one electrode is “base†and connect it with the assumed “base†with a black test pen. The other two poles are connected. This repeatedly switches the "base" until the two resistances are measured to be either large or small. If the resistance value measured twice is small, that is, the PN junction forward resistance, the tube is an NPN tube, and the black meter pen is a base. If the measured resistance values ​​are both large, that is, the PN junction reverse resistance, the tube is a PNP tube, and the black meter pen is the base.
2. Discriminate between the emitter and the collector. The theoretical basis for its measurement method is the amplification principle of the triode. As shown in the figure, when the tube type and the base are determined, if it is an NPN type tube, the black and red pen of the multimeter can be arbitrarily overlapped on the other two poles.
After pinching the black test lead and the base with your fingers, write down the multimeter indication value, then reverse the black and red test leads, and then retest once according to the above method, and then record the multimeter indication value. Compare the two readings. If the indication value is small, it means that the triode realizes the amplification function, the triode is turned on, the resistance is reduced, and the pin connected to the black test pen is the collector. The indication value is large, indicating that the power supply is reverse biased, the triode is turned off, and the resistance is large. In the case of a PNP type tube, the black and red test leads may be interchanged in the above method.
Use the multimeter R × 100 file to measure the forward resistance of the base and collector and the forward resistance of the base and emitter. If the measured values ​​are low resistance, the tube quality is good. If the measured forward resistance is very large or the reverse resistance is small, the tube is broken.
First, the multimeter
The multimeter is also called multi-meter and three-meter. It is a multi-function, multi-range measuring instrument. The general multimeter can measure DC current, DC voltage, AC voltage, resistance and audio level, etc. Some can also measure AC current and electricity. Capacity, inductance and some parameters of the semiconductor.
1. How to use the mechanical multimeter
(1) Familiarize with the meaning of the symbols on the dial and the main functions of each knob and selector switch.
(2) Perform mechanical zero adjustment.
(3) According to the type and size of the measurement, select the gear and range of the transfer switch to find the corresponding tick mark.
(4) Select the position of the test lead jack.
(5) Measurement voltage: When measuring voltage (or current), select a good range. If you use a small range to measure large voltage, there is a danger of burning the watch. If you use a large amount of process to measure small voltage, the pointer deflection is too small. Unable to read. The range should be chosen to deflect the pointer to about 2/3 of the full scale. If you do not know the magnitude of the voltage to be measured beforehand, you should first select the highest range and then gradually reduce it to the appropriate range.
a Measurement of AC voltage: Place one switch of the multimeter in AC and DC voltage, and the other switch is placed on the appropriate range of AC voltage. The multimeter's two test leads and the circuit under test or load can be connected in parallel.
b DC voltage measurement: put one switch of the multimeter in the AC and DC voltage, the other switch is placed on the appropriate range of DC voltage, and the “+†meter (red pen) is connected to the high potential, “- The test pen (black pen) is connected to the low potential, that is, the current flows from the "+" test pen and flows out from the "-" test pen. If the test leads are reversed, the pointer of the watch will deflect in the opposite direction, which is easy to bend the pointer.
(6) Measuring current: When measuring DC current, put one switch of the multimeter in the DC current block, and the other switch is placed on the appropriate range of 50uA to 500mA. The range selection and reading method of the current is the same as the voltage. The circuit must be disconnected first, and then the multimeter is connected in series to the circuit under test according to the current from "+" to "-", that is, the current flows from the red meter pen and flows out from the black meter pen. If the multimeter is connected in parallel with the load, the internal resistance of the meter head is small, which may cause the short circuit to burn the instrument.
(7) Measuring resistance: When measuring resistance with a multimeter, it should be operated as follows:
a Select the appropriate override. The scale of the multimeter's ohmic gear is not uniform, so the selection of the override gear should be such that the pointer stays in the thinner part of the scale, and the closer the pointer is to the middle of the scale, the more accurate the reading. Under normal circumstances, the pointer should be pointed between 1/3~2/3 of the scale.
b ohms zero. Before measuring the resistance, short the two test leads and adjust the “ohmic (electrical) zero adjustment knob†so that the pointer just points to the zero position to the right of the ohmic scale. If the pointer cannot be adjusted to zero, the battery voltage is insufficient or
There is a problem inside the meter. And every time you change the override gear, you must perform ohms zero again to ensure accurate measurement.
c Reading: The reading of the meter is multiplied by the magnification, which is the resistance of the measured resistance.
(8) Precautions
a When measuring current and voltage, it is not possible to charge range
b When selecting the range, first select the big one, then select the small one, try to make the measured value close to the range.
c When measuring resistance, it is not possible to measure with electricity. Because the multimeter is powered by the internal battery when measuring resistance, if the live measurement is equivalent to accessing an additional power supply, the meter may be damaged.
d After use, the switch should be in the maximum gear or neutral of the AC voltage.
2, the use of digital multimeter
Nowadays, digital measuring instruments have become the mainstream, and there is a trend to replace analog meters. Compared with analog instruments, digital meters have high sensitivity, high accuracy, clear display, strong overload capability, easy to carry, and simpler to use.
(1) Before use, you should carefully read the relevant instruction manual and be familiar with the functions of the power switch, range switch, jack, and special socket.
(2) Set the power switch to the ON position.
(3) Measurement of AC and DC voltage: If necessary, set the range switch to the appropriate range of DCV (DC) or ACV (AC), insert the red test pen into the V/Ω hole, insert the black test lead into the COM hole, and connect the test lead to the line under test. Parallel, the reading is displayed.
(4) Measurement of AC and DC current: Turn the range switch to the appropriate range of DCA (DC) or ACA (AC), insert the red test lead into the mA hole (<200mA) or 10A hole (>200mA), and insert the black test lead into the COM. Hole and connect the multimeter in
It can be used in the circuit under test. When measuring DC, the digital multimeter can automatically display the polarity.
(5) Measurement of resistance: Turn the range switch to the appropriate range of Ω, insert the red test lead into the V/Ω hole, and insert the black test lead into the COM hole. If the measured resistance value exceeds the maximum value of the selected range, the multimeter will display "1", then you should select a higher one.
Range. When measuring resistance, the red test pen is positive and the black test pen is negative, which is the opposite of the pointer multimeter. Therefore, when measuring polar components such as transistors and electrolytic capacitors, you must pay attention to the polarity of the test leads.
(6). Precautions for use
a If you cannot estimate the magnitude of the measured voltage or current in advance, you should first dial the measurement to the highest range and then gradually reduce the range to the appropriate position. After the measurement is completed, the range switch should be turned to the highest voltage and the power should be turned off.
b When the scale is full, the meter only displays the number “1†in the highest position, and the other bits disappear. In this case, a higher range should be selected.
c When measuring voltage, the digital multimeter should be connected in parallel with the circuit under test. When measuring current, it should be connected in series with the circuit under test. It is not necessary to consider positive and negative polarity when measuring DC.
d When the AC voltage is misused to measure the DC voltage, or the DC voltage is used to measure the AC voltage, the display will show “000â€, or the number on the low position will jump.
e It is forbidden to change the range when measuring high voltage (above 220V) or high current (above 0.5A) to prevent arcing and burn switch contacts.
How to judge the quality and polarity of ordinary three tubes with a multimeter
1. Determine the tube type and base. When measuring, first place the multimeter in the “R×100†or “R×1K†file, then assume that one electrode is “base†and connect it with the assumed “base†with a black test pen. The other two poles are connected. This repeatedly switches the "base" until the two resistances are measured to be either large or small. If the resistance value measured twice is small, that is, the PN junction forward resistance, the tube is an NPN tube, and the black meter pen is a base. If the measured resistance values ​​are both large, that is, the PN junction reverse resistance, the tube is a PNP tube, and the black meter pen is the base.
2. Discriminate between the emitter and the collector. The theoretical basis for its measurement method is the amplification principle of the triode. As shown in the figure, when the tube type and the base are determined, if it is an NPN type tube, the black and red pen of the multimeter can be arbitrarily overlapped on the other two poles.
After pinching the black test lead and the base with your fingers, write down the multimeter indication value, then reverse the black and red test leads, and then retest once according to the above method, and then record the multimeter indication value. Compare the two readings. If the indication value is small, it means that the triode realizes the amplification function, the triode is turned on, the resistance is reduced, and the pin connected to the black test pen is the collector. The indication value is large, indicating that the power supply is reverse biased, the triode is turned off, and the resistance is large. In the case of a PNP type tube, the black and red test leads may be interchanged in the above method.
Use the multimeter R × 100 file to measure the forward resistance of the base and collector and the forward resistance of the base and emitter. If the measured values ​​are low resistance, the tube quality is good. If the measured forward resistance is very large or the reverse resistance is small, the tube is broken.
ZGAR LEA BOX Disposable
ZGAR electronic cigarette uses high-tech R&D, food grade disposable pod device and high-quality raw material. All package designs are Original IP. Our designer team is from Hong Kong. We have very high requirements for product quality, flavors taste and packaging design. The E-liquid is imported, materials are food grade, and assembly plant is medical-grade dust-free workshops.
Our products include disposable e-cigarettes, rechargeable e-cigarettes, rechargreable disposable vape pen, and various of flavors of cigarette cartridges. From 600puffs to 5000puffs, ZGAR bar Disposable offer high-tech R&D, E-cigarette improves battery capacity, We offer various of flavors and support customization. And printing designs can be customized. We have our own professional team and competitive quotations for any OEM or ODM works.
We supply OEM rechargeable disposable vape pen,OEM disposable electronic cigarette,ODM disposable vape pen,ODM disposable electronic cigarette,OEM/ODM vape pen e-cigarette,OEM/ODM atomizer device.
Disposable E-cigarette, ODM disposable electronic cigarette, vape pen atomizer , Device E-cig, OEM disposable electronic cigarette
ZGAR INTERNATIONAL TRADING CO., LTD. , https://www.zgarecigarette.com