If you understand a multimeter, please enter, the use of a multimeter

The bad part is the transformer, the transformer in the circuit can be used for the audio output transformer for transistor radio, the secondary is used as the primary of the step-up transformer, the tap in the middle of the primary is not used, and the taps at both ends are used as the secondary of the step-up transformer. If you can't find a suitable transformer, you can also use the silicon steel sheet of the radio output transformer to make your own, and use a high-strength enameled wire with a diameter of 0 25mm for 110 turns for the primary stage, and a high-strength enameled wire with a diameter of 0 21mm for 520 turns for the secondary. A layer of insulating paper should be added between the primary stages, and attention should be paid to the eponymous end of the primary stage coil.

If the 500 type multimeter is broken with the head coil, it is recommended not to repair it, because even if you repair it, it will affect the accuracy of the meter, and the 500 type watch is also old-fashioned. It is recommended that you change a 47-type multimeter, it is OK to use, you want to buy a genuine brand, I used to use the 500 type and then there was a problem with the meter head, so I changed the Kehua brand produced in Nanjing, and I am very satisfied with it!

Millimeter diameter on the line, about 280 turns, in the end, to see the accuracy can only be winded, find a voltage source to try it. Because of the quality of the enameled wire, even if the voltage measurement is very accurate, other functions may not be accurate, because the internal resistance is definitely different from the original.

There is almost no chance of fixing. The repaired parameters will not be the same as the original, and the accuracy is not ***.

If you want to practice your hands, you can find a meter head with 50 microamperes and about 1k internal resistance. After installation, it must also be adjusted before use. But it will not reach the original accuracy.

The enameled wire inside the meter head is usually millimeter in diameter.

Upstairs, what are you talking about?

The enameled wire in the meter head is very thin, and the precision is high, the repair rate of the old-fashioned watch is very low, and the accessories are not easy to find, so I suggest you buy a new watch, if the economy allows, the digital watch of the internationally renowned brand fluke is the best, and many engineers and scientific research units use it, ** in a few hundred yuan to several thousand yuan, and the function of measuring capacitance and inductance.

The multimeter is a precision instrument, his precision all depends on the meter head, I said you don't want to wrap yourself, it will affect the accuracy. Buy a *** multimeter, and now ** is not very expensive.

The multimeter is a precision instrument, or I advise you to buy a new one, otherwise it will not be good.

It's easy to get it yourself. It is advisable to buy another one.

Brother, I read their answers, and I still advise you to buy one and forget it, because none of the answers will work for you, hehe.

The accuracy of the meter coil is high, and you are here.

Multimeters are cheap nowadays. 、

I have 4 broken pieces on my hands, but the meter head is good.

You have to go to Huai'an to find me. Send you.

Where are you, I have Wuxi 500, now I don't need it. It is recommended not to fix it.

I did high school physics problems in Khan

Here's how to use a multimeter:

1. When using the multimeter, it should be mechanically zeroed and the pointer should be reset to zero.

2. When measuring the resistance, select the appropriate magnification, so that the pointer is in the middle of the scale, and the multimeter is adjusted to the ohm file, and the measured resistance and the multimeter can be connected in series or in parallel.

3. When measuring the current, you should select the appropriate range gear and connect the multimeter in series in the circuit under test. Before measuring, the circuit should be disconnected, and the red and black pen of the multimeter should be connected in series between the two points that are disconnected, and the pointer size of the current should be checked to calculate the measured current.

Precautions for the use of multimeters:

A good habit to develop when using a multimeter is to look at the correct gear placement before each measurement. If you develop such a habit, the chance of burning your watch will be greatly reduced.

The range should be selected so that the pointer indication is around two-thirds of the full scale as far as possible, and the reading is more accurate. If you don't know the size of the voltage and current to be measured, you should select a large number of ranges, and then readjust the range according to the size of the reading to make the reading accurate.

When measuring resistance, it is necessary to re-zero after changing the range to make the reading accurate. If the zero position is not adjusted, it means that the battery voltage in the meter is insufficient, and the battery should be replaced.

**When measuring the resistance, the power supply should be cut off for operation, and it should also be noted whether there are other components to form a parallel circuit with the resistor under test, and if necessary, the resistance can be soldered from one end of the circuit and then measured. For circuits with electrolytic capacitors, measure the capacitors after they have been discharged.

How to use the multimeter: Before use, you should be familiar with the functions of the multimeter, and correctly select the gear, range and pen jack according to the object to be measured.

When the size of the measured data is unclear, the range switch should be set to the maximum value first, and then switch from a large range to a small range, so that the instrument pointer can indicate more than 1 2 at the full scale.

When measuring the resistance, after selecting the appropriate magnification level, the two table pens touch so that the pointer points to the zero position, if the pointer deviates from the zero position, the "zero" knob should be adjusted to make the pointer return to zero, so as to ensure the accuracy of the measurement results. If it cannot be zeroed or the digital display meter sends out a low voltage alarm, it should be checked in time.

When measuring the resistance of a circuit, the power supply of the circuit under test must be cut off, so as not to destroy the live measurement. When using the multimeter for measurement, it is necessary to pay attention to the safety of people and instrumentation equipment, and do not touch the metal part of the meter pen with your hands during the test, and do not allow live switching gear switches to ensure accurate measurement and avoid accidents such as electric shock and burning of the instrument.

Multimeter purchase tips

1. The number of digits and accuracy of the multimeter: The number of digits and accuracy are the most basic and important indicators of the multimeter. Generally speaking, the higher the number of digits displayed in the multimeter, the higher the accuracy, and vice versa.

2. Measurement method and AC frequency response of multimeter: The measurement method of multimeter is mainly for AC signal measurement, with the change of AC signal frequency, various frequency responses appear, which affects the measurement of multimeter. There are generally two ways to measure AC signals with a multimeter:

The mean and true RMS values are measured.

3. Function and measurement range: Different multimeters, their manufacturers will design different function measurement ranges. Ordinary multimeters can test AC and DC voltage, current, resistance, on/off, etc., but some multimeters do not set the current function in order to reduce costs.

4. Measurement stability and protection: a good multimeter has good self-protection, like some multimeters will automatically generate a buzzer alarm ...... when the wrong meter pen line is insertedThe purchase of multimeters, do not blindly covet cheap, to be practical and easy to use.

To use the multimeter, you only need to adjust to the mode you want to test, turn on the switch and then press and hold the electric rod, the specific steps are as follows:

Materials: 1 multimeter, 2 electric rods.

1. Twist the switch, find the switch in the middle of the multimeter, twist the switch in the counterclockwise direction, and twist it once to come to the mode of AC voltage.

2. Select the voltage, twist it again and it will come to the DC voltage mode, select the voltage you want to test, and turn on the switch next to it.

3. Touch the electric rod to the positive and negative poles, insert the second jack below into the fourth jack, and then touch the electric rod to the positive and negative poles of the electricity, so that this multimeter can test the voltage.

The use of the multimeter is explained as follows:

Material preparation: multimeter.

1. Before use, you should carefully read the relevant instruction manuals and be familiar with the functions of power switches, range switches, jacks, and special sockets.

2. Put the power switch in the ON position.

3. Measurement of AC and DC voltage: dial the range switch to the appropriate range of DCV (DC) or ACV (AC) according to the need, insert the red watch pen into the V hole, insert the black watch pen into the COM hole, and connect the watch pen in parallel with the tested line, and the reading will be displayed.

4. Measurement of AC and DC current: turn the range switch to the appropriate range of DCA (direct current) or ACA (AC), insert the red watch pen into the MA hole (200 mA) or 10A hole (200 mA), insert the black watch pen into the COM hole, and connect the multimeter in series in the tested circuit. When measuring straight flow, the DMM automatically displays the polarity.

5. Measurement of resistance: Dial the range switch to the appropriate range, insert the red watch pen into the V hole, and insert the black watch pen into the COM hole. If the measured resistance value exceeds the maximum value of the selected range, the multimeter will display "1", and a higher range should be selected.

When measuring resistance, the red pen is positive and the black pen is negative, which is the opposite of an analog multimeter. Therefore, when measuring polarized components such as transistors and electrolytic capacitors, it is necessary to pay attention to the polarity of the stylus.

Precautions for the use of multimeters:

1. If it is impossible to estimate the size of the voltage or current to be measured in advance, it should be measured once in the highest range, and then gradually reduce the range to a suitable position according to the situation. After the measurement, the range switch should be turned to the highest voltage and the draft meter source should be turned off.

2. When the full range, the instrument only displays the number "1" in the highest position, and the other digits disappear, so a higher range should be selected.

3. When measuring voltage, the digital multimeter should be connected in parallel with the circuit under test. When measuring the current, it should be connected in series with the circuit under test, and there is no need to consider the positive and negative polarity when measuring the straight flow.

4. When the AC voltage is misused to measure the DC voltage, or the DC voltage is misused to measure the AC voltage, the display screen will display "000", or the number on the low position will jump.

5. It is forbidden to change the range when measuring high voltage (above 220V) or high current (above ) to prevent arcing and burning the switch contact.

6. When "batt" or "lowbat" is displayed, it means that the battery voltage is lower than the working voltage.