Basics: Detection Methods Used And Experience Of Electronic Components

Components detection is an appliance repair basics, how to accurately and effectively detect the components of the relevant parameters to determine whether components of the normal, not a stereotyped thing, must be based on the different components in different ways to determine whether the normal components. Especially for beginners, mastery of commonly used components of the detection method and experience is necessary, the following test on the common experience of electronic components and methods are introduced for on the test.

One resistor detection methods and experience:

1? Fixed Resistors Detection. A? The two tables document (regardless of positive and negative) were the two ends of pin-phase with the resistance can be measured by actual resistance. To improve the measurement accuracy, the measured resistance should be based on the size of the nominal value to select the range. As the scale of the nonlinear Ohm's block, it's the middle of a more sophisticated indexing and should therefore be directed to the pointer value fell as much as possible the middle scale position, that is, the start of full scale of 20% to 80% within the arc to make the measurement more accurate. According to different level of resistance error. Reading between the nominal resistance were allowed ± 5%, ± 10% or ± 20% error. If not match, beyond the error range, it indicates that the value of a variable resistance value. B? Note: the tests, particularly in the resistance measured over dozens of k resistor, the hands do not touch the table and the resistance of the conductive part of the document; be detected resistance welding down from the circuit, at least to open a welding head, in order to avoid circuit The other components of the test impact, resulting in measurement error; color ring the resistance to the Israeli Central despite signs to determine, but is best when used with Multimeter Test the actual resistance.

2? Cement resistance testing. Resistance testing of cement and testing methods and precautions identical to normal fixed resistor.

3? Fusing Resistors Detection. In the circuit, open circuit when the fuse resistor fuse, may make judgments based on experience: if found to fuse resistors or charred black surface, it can be concluded that the overloaded by more than its current rating due to many times; If the surface without any trace of the open, it indicates that the current flowing through exactly equal to or slightly larger than its rated fuse value. For the surface without any trace of the fuse resistor to judge good and bad, can make use multimeter to measure the R × 1 block, in order to ensure measurement accuracy, should fuse resistors from the circuit on one end of the next weld. If the measured resistance is infinite, then illustrate the open fuse resistors are invalid if the measured resistance falls far short of the nominal value, that value of resistance change, we should not be used. Maintenance practices found that a small number of fuse resistors in the circuit is short-circuit breakdown phenomena, testing, also should be noted.

4? Potentiometers Detection. Check potentiometer, the first rotating handle to turn and see rotating handle rotation is smooth, Switch Are flexible, switching through, on and off, "a click" sound is crisp, and hear potentiometer and the resistance of the contact point within the body of a noise, if any "imperfections" sound, indicating poor quality. Test with a multimeter first potentiometer resistance according to the size of the measured, select the appropriate resistance gear good multimeter, and then the following method can be tested.

A? Measured with a multimeter ohm block "1", "2" ends, the reading should be nominal potentiometer resistance, such as the multimeter pointer difference between the number of fixed or resistance, is that the potentiometer damaged. B? Testing activities potentiometer contact arm and the resistance film is good. Measured with a multimeter ohm file "1", "2" (or "2", "3") ends of the potentiometer shaft counterclockwise to close by the "off" position, then the smaller resistance the better. Handle clockwise rotation axis and then slowly, the resistance value should be increased gradually, first in the pointer table should be a smooth move. When the spin axis to handle the extreme position "3", the resistance should be close to the nominal value potentiometer. If the multimeter pointer handle potentiometer shaft rotation in the process of beating phenomenon, indicating a poor contact of the fault contact activities.

5? Positive temperature coefficient Thermistor (PTC) detection. Detection, with a multimeter R × 1 block, concrete can be two-step operation: A? Room temperature test (room temperature close to 25 ); the two tables document contact with the two pin PTC thermistor to detect the actual resistance, and with compared to the nominal resistance, and the difference shall be within the ± 2 normal.

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