Meanings of symbols and letters on the multimeter
ACA (alternating current)
DCA (direct current)
DCV is direct current voltage
ACV is alternating voltage
The diode mark above is to test whether the circuit is conducting.
HZ is the frequency
The plug-in line com is the common terminal, and the other line selects the jack according to the physical quantity to be measured
interface:
The Cx interface is the interface of the capacitance to be tested.
PNP NPN: To measure the magnification of the triode, first switch the meter to the hfe position, root
According to the labeling of each pole and the characteristics of the triode to be tested, insert it into the corresponding hole.
COM: Common interface for current, voltage diode, resistance, and frequency tests.
All other interfaces indicate the type and scope of the measurement.
What do the symbols on the multimeter represent
Turntable logo, clockwise:
OFF shutdown, mV AC/DC millivolt voltage, V~AC voltage, V-DC voltage, Ω resistance,
Diode, continuity test, capacitance, frequency, triode magnification, temperature,
μA AC/DC microamperes, mA AC/DC milliamps, A AC/DC amps, off
The top row of buttons, from left to right:
SELECT range selection;
Hz/DUTY Hertz/signal duty cycle;
HOLD freezes, locks;
RANGE range selection;
REL read
Note that there is a string of letters 10sec MAX below the 10A logo, which means that when using this jack for measurement, no more than 10 seconds is allowed.
Meanings of other symbols:
Ω ohm Measuring resistance value
V-Voltage Measure DC voltage
V～Voltage Measure AC voltage
A-Current Measure DC current
A～Current Measure AC current
—≯—Diode Measure the polarity of the diode
The hfe triode is used to measure the magnification of the triode β
The meaning of the symbols displayed on the multimeter
Multimeter is also called multimeter, three-purpose meter and multimeter. AC current, capacitance, inductance and some parameters of semiconductors (such as β).
(1)∽ means AC and DC
(2) V-2.5KV 4000Ω/V means that for AC voltage and 2.5KV DC voltage block, its sensitivity is 4000Ω/V
(3) A-V-Ω means that current, voltage and resistance can be measured
(4) 45-65-1000Hz indicates that the operating frequency range is below 1000 Hz, and the standard industrial frequency range is 45-65Hz
(5) 2000Ω/V DC means that the sensitivity of the DC block is 2000Ω/V
The symbols on the clamp meter and the shaking dial are similar to the above symbols (others cannot be written all because of the wrong format of the symbols, 'means the magnetoelectric system rectifier type with mechanical reaction force 'means three-level anti-external magnetic field' means horizontal placement)))
Attachment 1, Question: What is a multimeter
Multimeter is also called multimeter, three-purpose meter and multimeter. AC current, capacitance, inductance and some parameters of semiconductors (such as β).
Use of multimeter
(1) Familiar with the meaning of each symbol on the dial and the main function of each knob and selector switch.
(2) Carry out mechanical zero adjustment.
(3) According to the type and size to be measured, select the gear and range of the changeover switch, and find out the corresponding scale line.
(4) Select the position of the test lead jack.
(5) Measuring voltage: When measuring voltage (or current), choose a good range. If you use a small range to measure a large voltage, there will be a danger of burning the meter; if you use a large range to measure a small voltage, the pointer deflection is too small. Unable to read. The selection of the range should try to make the pointer deflect to about 2/3 of the full scale. If you do not know the magnitude of the measured voltage in advance, you should first select the highest range gear, and then gradually reduce to the appropriate range.
a. Measurement of AC voltage: Put one switch of the multimeter in the AC and DC voltage range, and the other switch in the appropriate range of AC voltage, and connect the two pens of the multimeter in parallel with the circuit or load under test.
b Measurement of DC voltage: Put one switch of the multimeter on the AC and DC voltage range, and the other switch on the appropriate range of DC voltage, and connect the "+" test lead (red test lead) to the high potential, "- "The test lead (black test lead) is connected to the low potential, that is, let the current flow in from the "+" test lead and flow out from the "-" test lead. If the test leads are reversed, the pointer on the meter head will deflect in the opposite direction, and it is easy to bend the pointer.
(6) Current measurement: When measuring DC current, set one switch of the multimeter to the DC current gear, and the other switch to the appropriate range from 50uA to 500mA. The range selection and reading method of the current is the same as that of the voltage. When measuring, the circuit must be disconnected first, and then the multimeter is connected in series to the circuit under test according to the direction of the current from "+" to "-", that is, the current flows in from the red test lead and flows out from the black test lead. If the multimeter is connected in parallel with the load by mistake, the internal resistance of the meter head is very small, which will cause a short circuit and burn the meter. Its reading method is as follows:
Actual value = indicated value × range / full deviation
(7) Measuring resistance: When measuring resistance with a multimeter, the following methods should be followed:
aSelect the appropriate magnification gear. The scale line of the ohm block of the multimeter is uneven, so the selection of the magnification block should make the pointer stay on the thinner part of the scale line, and the closer the pointer is to the middle of the scale, the more accurate the reading. In general, the pointer should be between 1/3~2/3 of the scale.
b ohm zeroing. Before measuring the resistance, the two test leads should be short-circuited, and the "ohm (electrical) zero adjustment knob" should be adjusted at the same time so that the pointer just points to the zero position on the right side of the ohm scale. If the pointer cannot be adjusted to the zero position, it means that the battery voltage is insufficient or there is a problem inside the meter. And every time the magnification gear is changed, the ohm zero adjustment must be performed again to ensure accurate measurement.
c reading: the reading of the meter multiplied by the magnification is the resistance value of the measured resistance.
