multimeter for dummies

So how to master the quality of these media to ensure smooth transmission of information, you need to rely on the verification of the Cable Testing Instrument. In addition, more than 90% of the network faults are caused by cable link problems, but these problems can not be checked in the shortest time only by visual or multimeter. During network construction, you must test the cable using a regular tester. In general, the network card will not strike

, such as servers, switches, and routers, resulting in paralysis of the entire network. 1. Site-Level Test By checking physical connectivity, connection matching, protocol matching, and data sending and receiving correctness, this test solves most of the problems that a single site cannot connect to the network. Generally, the cabling system of the network should undergo a comprehensive test at the certification level. No fault affecting connection and communication will occur in special cases.

chips. When debugging a driver, in addition to fully understanding the data sheet of the chip, and in the process of software height, we also need to see whether the signal level we expect to occur on the chip. For example, when we write the driver, we need to write the I/O port to operate the peripheral chip, when writing the corresponding I/O port, we know that the corresponding chip signal should be valid, sometimes we need to verify whether the expected occurrence, which requires an oscillo

Bluetooth serial port out of the problem, only can not receive, the baby also do not know where the reason. Every time you lose a lost, down to the board found can not be used. And I don't know why. Silly don't pull a few look at the program, look for problems. Watch it for a week. Later, the laboratory students with a multimeter!! The problem with the test is hardware. Multimeter in the baby here is to do

IC 2003 Drive RelayThe left figure 1~7 is the signal input (in), the 10~16 is the output signal (out), and the 8 and 9 are IC power supplies. The diagram on the right is the inner schematic of the integration block.2.1 Simple introduction of working principleAccording to the input and output characteristics of IC Driver 2003, it is referred to as "drive" "inverter" "amplifier" and so on, now frequently used model: TD62003AP. When the 2003 input is high, the corresponding output is low, the rela

probes. The data that needs to be measured has the maximum, minimum, and average values for each circuit. The average value is the focus of power debugging, and the maximum and minimum values are particularly important for the stability of the whole board. For example, a board processor end current maximum is 600mA, the minimum is 100mA, the average is 200mA, and the same B board maximum is 400mA, the minimum value is 150mA, the average is also 200mA, these two board B board will certainly be

The method for determining whether a FET is good or bad is totally different from that of a transistor. The following describes how to determine whether a FET is good or bad: 1. the multimeter is equipped with a diode; 2. the red pen is connected to d pole, and the black pen is connected to S pole. In turn, the quantity is connected to a pressure drop of V; 3. the red pen is connected to the G pole, and the black pen is connected to the S pole, but th

a computer or a USB device. We can use other USB devices to test whether the computer is faulty.If it is a computer problem. Is your computer damaged by viruses. Whether the USB driver is installed properly or the version is not compatible. There is no software conflict (first solve the Software Problem). Generally, a prompt is prompted to install the driver.If it is a computer hardware problem. We first use A multimeter to measure the four USB lines

PreparationI didn't buy the original board. I purchased the compatible board from the authorized supplier. The compatible board has some changes.In order to connect the computer with the source board and the compatible board, you not only need to connect the cable, but also need to download the corresponding driver for the compatible board I purchased to use USB cable connection, the driver depends on the compatible board. Contact the supplier. Note that different drivers are required for differ

bridge, forcibly boot or abnormal shutdown, there is the phenomenon of intense hair hot. When using a multimeter to measure whether there is a short-circuit, first disconnect the power supply, dial out the ATX power cord. Then the multimeter to the diode position, Red pen grounding, black table pen to test points, we call it the measurement of the ground resistance. 1. Measure the 3.3V on the ATX power s

The motherboard leakage Solution method: In general, the motherboard is now a bad power supply heart slice is very likely, the power supply heart piece is broken, the CPU generally no temperature, at this time you can use digital multimeter diode gear measuring inductance and ground, if the multimeter is called a long word, power supply heart is good, if the inductor to the ground short-circuit, the mother

parameter. After dealing with the fault, we should make clear the cause of the fault, draw up the corresponding countermeasures, avoid the recurrence of similar failures as far as possible, and record the network management log for future reference and accumulate operation and maintenance experience. 2.2 General wiring troubleshooting common diagnostic tools General wiring Troubleshooting common diagnostic tools include: Hardware troubleshooting tools, software troubleshooting tools, as well

/between a space), insert the original system disk repair system, the system will be automatically compared to repair. 　　Step 5: If the computer keyboard fails to continue, set the optical drive in the BIOS to insert the original system into the first boot device and press R to select "Repair Installation". 　　Step 6: If the computer keyboard fails, it is recommended to reload the operating system. (1) After the power-on computer can not detect the keyboard to check the keyboard interface is

hard disk interface set as the upper end) of the SMD resistance components in a component (its label on the 1r00) on the surface as if slightly puffed up the bubble skin, a shave with a finger is lost, but there is no obvious burning mark on the component, only a metal point of the size of the needle. Use the Multimeter electric block to measure the element resistance to 128kω. And then use the multimeter

XP system computer Hardware common problem analysis is as follows: 1: The computer's motherboard capacitor damage to our graphics card is not normal use, the solution is that we directly use the capacitor on the motherboard to replace the nominal value can solve the problem. 2: The computer power switch can not be used normally, the Start button is not open after the computer, the solution we preferred to test the computer, the use of a multimeter c

well observed. When you are sure that the system is correct, the author (preferably please professional notebook repair master to check, it is best not to take apart) then open the display, will see the high pressure of dangerous board (high voltage) This is the High-voltage plate, the high-voltage plate insulation after removal we can find the entire high-pressure plate structure, The motherboard has 4 wires and high pressure board, then, the High-voltage plate through the chip distribution vo

with a working wavelength of 1310nm or 1550nm, and the best fiber-optic recognizer is the use of macro-bending technology to identify optical cables and test the transmission direction and power of optical cables online. 2, the fault locator (fault tracker). The device is based on the laser diode visible light (red light) source, when optical injection of optical fiber, if the fiber fracture, connector failure, bending over, welding quality, such as the failure of the same, through the light

slightly harder plastic (such as an abandoned floppy disk jacket), the size is equal to or slightly larger than the size of the key body, and in the position of the bar through the opening of After it is set on the stick, insert the key cap, and use this gasket to prevent the key cap and the key body stuck, you can repair the failure button; If due to spring fatigue, the cause of the tension of the shrapnel caused by the card key failure, then the special key body open, slightly stretching the

libraries implemented by Mock-python Ludibrio-Elegant Test doubles framework (mocks, stubs, Spy, and Dummies) implemented in Python. Responses-mock Request for Python Test ToolPak DoubleX-powerful Test doubles framework Freezegun-time travel through the mocking datetime module Httpretty-http The requested mock tool Httmock-requests's mock tool that supports Python 2.6+ and 3.2+. Pretenders-Fake server for tes

function object. This reference value is NULL in a global context scenario. Such a data structure constitutes a one-way list, each of which points to the outer context of the scenario.For example, the closure model of our example above should be this way, the SayHello function is at the bottom, the upper layer is the function greeting, the outermost is the global scene. For example: So when SayHello is called, SayHello will find the value of the local variable text in context, so the "Hello Clo