Car repair rest of my life, did not know these detection methods DMM on vehicle maintenance


Automotive repair industry Is a large group, there are only tens of thousands of Henan repair shop every diesel injection Carts to repair the master class, a lot of master say even a multimeter never used, repair the Car can really master the integration of mechanical and electrical maintenance Is already a lot, but when it comes to digital multimeter, general master Will use, but these never used in detection methods, today we Will go together to share digital multimeter detection method.

DMM resIstance detection: Many master Will use a meter to measure, but the real accurate measure the resIstance value, also the paste in confused, especially when some of the smaller resIstance value detection element, it Is necessary to know how much internal resIstance of the multimeter, the resIstance of the detected resIstance Is the real, the specific method: digital multimeter to the lowest resIstance profile, then the two pen multimeter contact with each other and read a resIstance value, the resIstance value Is the multimeter test leads if used with a measurement, the resIstance value further comprIses a special test wire, thIs time should be measured before multimeter adjusted to zero, or subtracting the measured resIstance Is the internal resIstance of the original resIstance.

Sometimes multimeter continuity does not ring in response Sometimes, in the end Is the Editor, look at it, when using a digital multimeter, selecting multimeter conduction test file, in that the diode Is on multimeter dIsk file, in a case where the confirmation member to be measured conductivity uncharged, break the circuit must be measured, but only touch pen two-terminal element, respectively, if the resIstance Is less than 150 ohms, multimeter just beeps, if the resIstance of about 150 ohms, multimeter does not ring, but many mechanics habit detection method has been applied through the wire barrier, so it Is to be Careful, after all, a large resIstance value when the buzzer does not ring influence your judgment efficiency.

Have you ever used a multimeter to test too short to ground it? In fact, the presence of impermIssible connection between the wire and the Ground we said short detecting a short circuit in the Car these procedures: detecting a short circuit should be closed before the ignition switch, must be cut off, dIsconnecting the plug, and a stroke table the sense terminal, the other surface of the table body and a cleaning unpainted stroke, thIs time reading the resIstance value of the multimeter, should be greater than 100 kilohms, such asIf the measured resIstance Is less than 100 kohms, or even smaller, a short to ground should suspect, a further verification at the buzzer file.

The most common use of the continuity check your right, conductivity detection method most commonly used in the actual maintenance of a single wire: closed Car keys, determining a measured lead a case where after power measurements, the multimeter and the two wire ends of the stroke table, digital multimeter dIsplay Is less than 10 ohms, then the good conducting wire, such as wire resIstance greater than 10 ohms, the high resIstance line determined not to be replacement, or detect the connector Is not rusted.

with a measuring current of very few people, though not much used at the time of vehicle maintenance, but for troubleshooting necessary, but we must dIstinguIsh between AC and DC current measurement current , we used a multi-Car Is the direct current, the current detecting special attention hands insertion hole, select the appropriate range according to the magnitude of the current, such as the range does not know when the maximum range, the multimeter series in the circuit, and power-off at access red pen then positive, then negative black pen, power current Is observed multimeter index value.

Upon detection of the multimeter and transIstor capacitance, we must dIstinguIsh between positive and negative components, if the resIstance profile Because our red lead with positive voltage, the black pen with a negative voltage, voltage of the diode Is to be noted 1-3 character detection, a voltage of about 9-11 meter pointer with characters, it Is easy to burn out the electronic components, so as not to switch knob in the measurement, in order to avoid arc burned contacts.

in the actual repair process, using the multimeter should also take note of these, measured look at the file, do not look do not measure, before the first zero amount of adjustment did not measure, measurement with one hand to do, safe and secure, test uncharged R, C measured before dIscharge, I want to test in series, in parallel to measure U, polarity Is not reversed, the insulation into the habit, the dial should put a positive reading was accurate, long-term when not in use The battery should hold against.