If you want to check the circuit for a short. First, cut the power to the line, then unplug each load switch and use the ohms of your multimeter to block the resistance between the two wires. Under normal circumstances, the higher the resistance, the better. If you decide whether the circuit is grounded or not, you can use a multimeter ohms file. Measure the resistance of each wire to ground. The greater the better. It is important to note that using a multimeter to measure whether a circuit is shorted and grounded is not accurate. It shouldn't be. If the ground or short resistance is small, you can use a multimeter to detect it if the resistance is slightly larger. A multimeter will not detect it. It is located in a 380V low voltage circuit.how to test pcb board with a multimeter? Measurements should be made with a 500V megohmmeter, between the lines or to ground. It should exceed 0.38 euros. Otherwise, it fails.
First of all, we need to distinguish between the energized line and the zero line. Ground line: turn the multimeter to AC voltage, gear higher than 220 V. Insert the red probe into the voltage hole, the black probe is not inserted. Then insert the red probe into one of the sockets and observe the reading.
The largest reading is the solid line, the smaller reading is the zero line, and the reading that basically doesn't move is the ground line. If two readings are low and one is high, the ground wire is not grounded and the ground wire is connected to the zero wire. The second step does not require measurement. Switch the multimeter to the "short" test function (if there is no resistance test) and connect the red and black markers to the circuit ground and power supply ground, respectively. If the test result is a short circuit or low resistance, the circuit is grounded, otherwise it is not grounded.
To check leakage and grounding, set the multimeter at 200m m. For example, to measure the insulation of the equipment, connect one end of the probe to the equipment casing or ground and the other end to the line. When measuring insulation, do not touch the probe with your hand to prevent measurement errors. Turn the resistance gear of the multimeter to 20K or 200K, turn off the main power supply and the load power supply, connect the fire wire of the multimeter and the ground wire of the multimeter with the singing needle to check the resistance value, and then connect the zero wire and the ground wire with the singing needle to observe the resistance value twice.
If it does not exceed 7.3 or 14.5 times more, it indicates that there is an information leak in the energized line or zero wire with resistance value connected by the Chinese society at that time. Many electricians will tell you to disconnect all student power and measure the resistance between the two line designs with the smallest resistance gear (or diode gear) to see if it has approached 0 ohms (or the diode gear shows 0). If one is close to 0, it is essentially all that is needed to make a judgment call that the two lines are shorted together. Similarly, measure the distance from this line to ground to see if it can be in the exact same state. If it can not be proved that this line is grounded, this teaching method is certainly feasible, but in our actual management of the work, pcblink 1oz vs 2oz Coppermany other local governments are not convenient to cut off the power supply. Are the results of continuous data measurements reasonably practicable?
The essence of voltage is potential difference. As long as the voltage between two lines is zero, the resistance file can be used to measure.
1. Suppose there is a short circuit between lines A and B. There may be a voltage (say 220 V) on the neutral line between lines A and B. The potential on the neutral line between lines A and B is the potential difference between the two lines. The potentials on their wires are potential a and potential b. Many people for the first time think that if we measure directly with a resistance gear, we must disconnect the power supply to lines A and B respectively, and then we can measure. This idea is not wrong, but more conservative.
2. Switch the multimeter directly to the AC voltage range, select the highest range, such as AC1000V, and then use the AC voltage range of the multimeter to measure wires A and B. The AC voltage range of the multimeter will be used to measure the potentials of the two wires. If there is a high voltage (e.g. 200V) between the two lines, it can be proved that the potentials A and B are not equal, i.e. there is a voltage difference between potential A and potential B. The potentials of the two lines are not equal and the two lines are not short together.
3. If line A and line B cannot be measured with AC voltage, to be sure, choose a DC voltage, say 1000V, and measure the voltage between them to confirm that there is no DC voltage. This proves that potential a and potential b are equal. Note that being equal does not mean that they have no voltage to the zero line N. For example, lines A and B have 220 V to the zero line N, but the voltage between them is also 0 V... At this point, the resistance between the two wires can be measured using the smallest resistor. If it is close to 0 ohms, it means that the two wires are shorted together.
4. For whether or not to pass the measurement of the ground, there is also the option of using the research methods described above need to make a simple measurement. The idea is to understand the ground as an ordinary line. However, for a general measurement of whether the students have access to the ground, it is possible to effectively use a megohmmeter to measure the insulation resistance (usually, the insulation is 5 megohms). At this point, it is necessary to disconnect the power supply technique for data measurement.
