vom multimeter

I. coaxial cable Detection1. After the cable enters the water, we have tested the change of Characteristic Impedance. When the cable enters the water due to moisture and the TV signal passes through the cable, the measured level is lower than the specified loss value of the cable. According to the length of the cable inlet and damp time, the loss attenuation value varies depending on the degree of corrosion and oxidation Rust of the internal and external cables.Under the face of moisture, water

standard method, its capacity does not need conversion. Note that the pressure value and operating temperature are generally indicated under the capacity. See Figure 9. Figure 8Figure 9Measurement of capacitance:The general multimeter does not have a special measurement of capacitance capacity of the gear. In most cases, we measure some of the capacitance's characteristics in the following ways:1) measure its leakage resistance. Leakage resistance S

expressed by the rise or fall of the level on the interrupt line. Obviously, there are two kinds of edge trigger modes. One is that the center disconnection changes from low level to high level, which is called the rising edge trigger, and the other is that the center disconnection changes from high level to low level, which is called the falling edge trigger. In general, the interrupt trigger methods include Level Trigger, rising edge trigger, and descent edge trigger. An important step in the

Previously, I often reversed steps (3) (4) and found many problems. Remember, you must first disconnect the DSP and then perform other plugging operations.2. The V kernel voltage of DSP6000 is always used to measuring whether the power supply and ground are short-circuited with A multimeter before power-on during PCB debugging. That day, the problem occurred. I used a multimeter (black leather) to test the

The symptoms of capacitance damage are: 1. Automatic restart of computer without reason 2, boot time to boot several times before starting 3. File loss 4, suddenly blue screen, etc... One, depending on the size of electrolytic capacitor, usually use multimeter R10, R100, r1k block for testing and judgment. The red and black pens are respectively connected to the cathode of the capacitor (before each test, the capacitor should be discharged), and

Philips display line tube is less, compared with the same grade Adi, the excitation waveform of the tube is not very good, the working temperature is high, and the damage of the line tube is much more obvious. This may be Tun, because like BU2508, 2520, 2522 is the product of Philips. The general design in order to allow the completion of the saturation of the line pipe, often in line with the row to promote the transformer between the current limiting resistor in parallel a capacitor and a rev

. These experiments can basically meet the needs of professional courses such as automotive electrical equipment for basic electrical and electronic technology skills. In order to do better, you can also add some practical lab content related to the professional needs. For example, capacitors are used in automobiles, but there is no requirement in the measurement content in the teaching materials. You can add experimental items for measuring capacitors. There are many sensors on automobiles, som

Now a lot of people are accustomed to using mobile phone to entertain, but neglected the existence of the computer, causing the computer for a long time does not boot and caused a period of time after the computer automatic damage, often appear this situation will feel panic, so I am here to enumerate a few common problems and solutions, hoping to help everyone. 　　Tools/raw Materials Computer One Multimeter A Alcohol Screwdriver Keyboard 　　Meth

Principle of stepper motor According to common sense, the wiring of stepper motor depends on the color of the wire. However, the color of the stepping motor produced by different companies is different. Especially foreign stepper motors. Then, the stepper motor wiring should be made with a multimeter. The internal structure of stepper motor is as follows: We can see that ,~ A is connected, B and ~ B is China Unicom. So, a and ~ A is a group of A

a good one. Hard disk adapter card (or multi-function card) compared with the hard disk adapter card, the problem is whether the hard disk adapter or the hard drive itself. ⑥ observe the stepper motor end of the stall pin is stuck to die, such as die, hand back to the starting position. The above steps, users need to carefully check, test, analysis, find out the bad components for repair, or replace the hard disk adapter card. After the above treatment, as long as it is not the hard disk bod

Optical Fiber Network Fault Test Equipment Analysis In recent years, as people have higher and higher requirements on the rate of broadband, because the performance of optical fiber is better than that of copper cable, it has been widely used in the backbone construction of broadband projects. At the same time, due to the increasing coverage of optical fibers, fiber failure detection is becoming more and more important. What methods can be used to eliminate faults of Optical Fiber Components? F

. The power system is connected by an electric network and a thermal network (or a hydraulic system. Ii. multiple choice questions 1. When two resistors with the same rated voltage are connected in series to the circuit, the resistance with A large resistance value (A) is obtained ). A. There is no significant difference between B and C. 2. The conversion switch of the multimeter is implementation (). A. Switch of various measurement types and ranges

switch. Because the laser head is the most precise part of the optical drive, but also the most expensive part, the individual can not repair! For LG DVD optical drive control circuit and servo circuit, if the main bearing does not turn, to check the bearing and the circuit board data Line (on the right) connection is intact, the circuit board connected to the drive chip between the circuit is smooth. If the bald-headed self-test issued a red light, but do not seek, then look at the control of

be that there is no cross-line trouble in the production of direct connections). In order to cooperate with the use of direct connections, in the drawing board, connect the rxd pin of the main control chip to the three-pin serial port, and the txd pin of the main control chip to the two-pin serial port, so that the serial port on this development board is not a standard serial port, that is to say, 2 is changed to TX, 3 is changed to RX, and the direct connection should be used when connecting

Figure: General block Diagram (right-click on the New tab to open the picture for a larger view)Figure: Circuit board layoutTest point1. Add the test point to the 4055 to the back level R12. Set the test points R8 and R7 in the 34,712-way output respectivelyCommissioning Process1. Get the PCB template, test the short circuit and the circuit breaker with a Multimeter control plan2. Welding components1. First think about the welding sequence of componen

, and you are not sure that the hardware engineer's operation is completely correct, is not every line is connected to the right, then you must get the patch diagram and schematic, and then the board on the fly line a line of check again. If it's accurate, then you're going to start.(2) When your hardware engineer does not provide you with the hardware board pin specific on the board where the instructions, you must get a patch map.(3) In addition, the regular patch diagram helps to improve the

Arduino pin output level will be reversed, that is, the Arduino output high, the chip receives low, and vice versa! As long as you know this, the rest is almost the same as developing the normal output pin.Let's try out a test project first.In the test project, we use the multimeter voltmeter (20V stop) to simulate the 12V chip, that is, the red line of the multimeter, the blue wire, the

pin of the serial port, so that the serial port on the Development Board is not the standard serial port, that is, 2 becomes tx,3 Rx, and the standard serial connection should use straight line. Look at a development board on the serial port is the standard serial port is also a non-standard serial port, it is essential to see how the schematic is connected!Overall: RS232 's DB-9 interface has three types of connections: Male to female, male to male. Mother to mother. Each of the three connecto

the serial port of 2, so this development Board is not a standard serial port, That is, 2 becomes tx,3 to Rx, and the standard serial connection should of course use straight line. Look at a development board on the serial port is the standard serial port is also a non-standard serial port, it is essential to see how the schematic is connected!In general: The connection line of the RS232 DB-9 interface contains three kinds: male to female, male to male, mother to mother. Each of the three conne

optical drive is older, you can consider a new switch. Because the laser head is the most precise part of the optical drive, but also the most expensive part, the individual can not repair! For LG DVD optical drive control circuit and servo circuit, if the main bearing does not turn, to check the bearing and the circuit board data Line (on the right) connection is intact, the circuit board connected to the drive chip between the circuit is smooth. If the bald-headed self-test issued a red ligh