Method for detecting resistance:

First, the appearance inspection

Check that the signs are clear, the protective paint is intact, without scorching, scars, cracks and corrosion, and the resistor is in close contact with the pin. For potentiometers, you should also check that the rotating shaft is flexible, elastic and comfortable. If there is a switch, check whether the switch action is normal, etc.

Second, the multimeter detection

1. When judging whether the resistance is good or bad with a pointer multimeter, you should first select the measuring gear, and then put the magnification gear knob in the appropriate gear. Generally, RX1 gear can be selected for resistors below 100 ohms, RX10 gear for resistors between 100 ohms and 1kohms, RX100 gear for resistors between 1kohms and 10kohms, RX1K gear for resistors above 100kohms.

2. After selecting the measuring gear, calibrate the resistance gear of the multimeter to 0. The method of calibrating 0 is: short-circuit the metal bars of the two probes of the multimeter, and observe whether the pointer reaches the position of 0. If it is not at the position of 0, adjust the pointer of the zero adjustment knob to point to the position of 0 of the resistance scale.

3. Then, connect the two probes of the multimeter to the two ends of the resistor respectively, and the probes should point to the corresponding resistance scale. If the probes are immobile and unstable, or the indicated value differs greatly from the indicated value on the resistor, it means that the resistor has been damaged.

4. When judging whether the resistance is good or bad with a digital multimeter, first adjust the gear knob of the multimeter to the appropriate gear of the ohm gear. Generally, 200 gears can be selected for resistors below 200 ohms, 200-2K ohms can be selected for 2k gears, 20-20K ohms can be selected for 20k gears, 200K-200M ohms can be selected for 2M ohms. The resistance of 2M-20M ohm is 20M, and the resistance of 20M ohm or more is 200M.

The content introduced above is the method to detect the quality of resistance. Through these simple detection methods, you can quickly detect the quality of resistance, which brings great convenience to your use.

What is the phenomenon when the resistance is broken?

When the resistance is broken, it is generally that the resistance becomes larger, and some of them will become smaller, or most of them are open.

What symptom is the blower resistance broken?

The blower resistance mainly controls the speed of the blower. If the blower resistance is broken, the speed of the blower is the same in different gears. After the blower resistance is broken, the air volume control knob loses its speed regulation function. It will lead to the inability to adjust the air output; There is no 1234 gear, only one air outlet; It should be a large air output; There are also some fans that don't work directly.

When the varistor is normal, its resistance is infinite. It is connected in parallel at both ends of the power supply, which plays the role of overvoltage protection. When the input voltage exceeds a certain value, its resistance suddenly becomes smaller, making the circuit short-circuited, forcibly shorting the fuse, and playing the role of protecting electrical appliances. Under normal circumstances, the inverter fast silicon is easy to break. If the rectifier silicon is broken, there is likely to be sudden overvoltage or overcurrent. Because of the trigger disorder caused by load disturbance and power fluctuation, the rectifier silicon will also be damaged, and the specific problems need to be analyzed according to the damage situation.

The reason why the fan resistance of automobile air conditioner will burn out continuously;

1, compressor or control circuit caused by short circuit.

2, condenser motor, compressor electromagnetic clutch, evaporator motor failure.

3. The fuse of the automobile air conditioning fan does not meet the requirements, and the current value is small.

4. There is a short circuit in the air conditioning system, which is caused by too much compressor load.