As one of the indispensable products in the field of electronic testing and maintenance, digital multimeters have become more and more widely used. A digital multimeter is a measuring instrument that converts measured data into digital quantities by using the principle of analog-to-digital conversion and displays the measured results in digital form. Compared with the pointer multimeter, the digital multimeter has the advantages of high precision, high speed, large input impedance, digital display, accurate reading, strong anti-interference ability, high measurement automation, etc., and thus is widely used and favored by users. This article refers to the address: http:// The high-end digital multimeter series launched by Shenzhen Festtech Technology Co., Ltd. covers the powerful function data communication true RMS multimeter (FT365/FT368), industrial data communication true RMS multimeter (FT335/FT338), wide frequency response True RMS multimeter (FT212/FT215/FT217) and automatic range multimeter (FT163/FT168/FT6/FT8). FT335/FT338 With the development of the automotive industry, more and more electrical equipment is now being applied to automobiles. When troubleshooting the electrical parts of automobiles, the multimeter is one of the most commonly used automotive electrical maintenance tools to test voltage, Current and resistance. The ultra-functional data communication true-effective multimeter (FT365/FT368) introduced by Faith Technology has been widely used in the automotive industry. Here are some examples of detecting the electrical part of the car to illustrate the application of the digital multimeter. 1. Automobile anti-lock braking system (ABS) detection. Due to the traffic environment such as road, climate, traffic management and driving quality, the car must be constantly braked and emergency braked. When the brake is pressed in an emergency, the braking force will reach the maximum immediately and the wheel will be locked. If the front wheel is locked first, the steering will fail; if the rear wheel is first locked, the car is prone to slip or tail. If the wheel speed sensor in the brake system is found to be malfunctioning, use a digital multimeter to measure the resistance of the coil. The resistance is greatly broken, and the resistance is small, so the sensor head needs to be replaced. 2, the car self-extinguish fault detection. When overhauling the EFI engine, maintenance personnel often tend to ignore the inspection of the power supply and the grounding wire. The computer must provide sufficient voltage and good grounding during normal operation. Other electronic controllers should also meet the same conditions, sometimes grounded. The line uses its own casing, and there is no special grounding. This should be taken care of during maintenance. In other cases, the power supply is poor, and the problem is mostly on the power supply line. For this, use a digital multimeter to check the battery voltage. Whether it is consistent with the computer and the electronic control voltage. In short, for the computer to check the power and ground wire when the normal code is output, you may be able to find the real cause of the fault. 3, the car engine shakes black smoke detection. The oxygen sensor installed in the front of the exhaust pipe muffler is a solid battery. In normal operation, it can emit an electromotive force of 0.25-0.85V, corresponding to the combustion condition of the lean mixture. Its electromotive force feedback is input to the 28th and 10th feet of the computer (ECU) to control the gasoline injection to achieve the best air-fuel ratio (14.7). In order to shorten the heating and heating process of the oxygen sensor, the sensor is electrically heated. See Figure 2 for a specific method of measuring oxygen sensing 车 on the vehicle (when measuring, use a high-impedance digital multimeter). When the test found that the electromotive force was zero, it indicated that the sensor was damaged, which caused the computer to misreceive the “lean†mixed gas signal. As a result, the fuel consumption of the vehicle increased and the exhaust gas emitted black smoke. With the new sensor replaced, the engine operation returned to normal, so the drop was eliminated. 4. Detection of automotive computer control systems. When testing the automobile computer system, it is strictly forbidden to disconnect the battery line when the engine is running, to prevent the generator from losing the load and causing the voltage to be too high to damage the computer. At the same time, since most automobile engine computers have permanent power supply, it is forbidden to disconnect the battery. Before disassembling the computer, it will avoid damage to the computer caused by the self-inductance potential, and it is forbidden to plug and unplug the computer-related components with inductive properties while the engine is running. When detecting the computer board and related components, the corresponding computer terminal connected to the injector should be found according to the circuit diagram or the actual line direction, and then use the digital multimeter's on-off gear to start from the determined computer terminal along the printed circuit of the computer. Look inside, until you find a triode or triode row, test whether there is damage, and you can quickly test the failure of the computer control system. 5. Fault detection and maintenance of automobile air conditioner failure. In the air conditioning system of a car, whether it is a manually controlled or automatically controlled air conditioner, the cutting and engagement of the electromagnetic clutch of the compressor is generally controlled by a computer. Therefore, in the failure of the automobile air conditioning system, a considerable part of the fault occurs on the computer. . (1) When testing the computer system of the car air conditioner, use the digital multimeter's measurement on-off gear, and look up from the determined air-conditioning control terminal a little bit along the computer's printed circuit until a triode or triode is found. Row, test for damage. (2) Set the air conditioning operation panel to the air conditioning and cooling operation state, connect to the base line to be confirmed using the voltage multimeter of the digital multimeter, turn on the A/C switch, which should display 5V, and display 0V when the switch is turned off. Test the two lines with this method and repeat the confirmation that the condition is the base. When confirming the emitter, generally if it is a triode row, its emission is mostly at both ends of the row. The end of the measuring and disconnecting block of the multimeter is connected to the grounding end of the computer, and the other end is connected to the grounding end which is considered to be the row, which can guide The pin of the pass is the emitter of the triode. (3) Remove the roughly determined triode from the board and use the multimeter's diode to measure the properties of the triode. (4) Select the measurement block of the triode of the digital multimeter, insert the base of the triode into B, and insert the other two legs into C and E respectively. If the displayed value is between 200 and 300, prove that the pin is inserted correctly, and C represents the set. Electrode, E represents the emitter. It is further determined whether the triode is of the PNP type or the NPN type. P is the positive electrode and N is the negative electrode. (5) When the selected transistor is to be soldered to the circuit board, use the digital multimeter's measurement on-off gear, and use the positive and negative test leads against the collector and emitter of the triode to control the base and the base of the board. Connect the wires and turn on the air conditioner to see if the multimeter shows continuity. If it is turned on, it proves that the transistor can be used. After the welding is completed, use a multimeter to measure that the pins should not be connected to each other. Through the above steps, the car air conditioner can be quickly repaired. From the above, the super-function data communication true-effective multimeter (FT365/FT368) introduced by Faith Technology is still widely used in the automotive industry. Of course, there are other application aspects that are not mentioned in this paper. I believe that the practical application of the digital multimeter automotive industry will continue to be discovered. Oval Series Sensor Automatic Dustbin Auto Trash Can,Oval Series Sensor Automatic Dustbi,Oval Series Sensor Dustbin,Oval Series Sensor Office Dustbin NINGBO ZIXING ELECTRONIC CO.,LTD. , https://www.zixingautobin.com
