Detecting breaks in wires with a multimeter
As the outer layer of the wire is wrapped with insulating skin, the internal breakpoints are difficult to see, and it is troublesome to detect them with the traditional multimeter, which needs to be used with a resistor, one section at a time, which is time-consuming and also easy to break the wires. And now the digital one is much simpler, connect one end of the wire with the phase wire, the other end is suspended. One hand pinch the tip of the black pen, the other hand holding the red pen, so that the tip of the wire along the insulation layer slowly from the end of the phase line connected to start moving backward. When the multimeter's voltage reading suddenly becomes small (equivalent to one-tenth of the original reading), from here back to the 15CM is the break point of the wire.
With this method only need to destroy a point of the wire to solve the problem, is not very convenient ah. This method can also be used to detect the break point of the electric blanket.
2. Use a multimeter to detect short-circuit faults in the circuit.
When the family's circuit has broken wires or circuit aging caused by a short circuit between the firewire and zero line, generally this short circuit point is difficult to determine where, then the resistance method with a multimeter can be easily found. After the line short circuit, you should disconnect the main switch, unplug all electrical appliances. The multimeter is placed in the resistance file, the two pens are connected to the fire line and zero line, if the resistance value is zero or very small can be concluded that the short circuit. It is necessary to measure the resistance value between the fire wire and the zero wire section by section, if necessary, you can cut off a section of wire to determine the short-circuit point.
As the outer layer of the wire is wrapped with insulating skin, the internal breakpoints are difficult to see, and it is troublesome to detect them with the traditional multimeter, which needs to be used with a resistor, one section at a time, which is time-consuming and also easy to break the wires. And now the digital one is much simpler, connect one end of the wire with the phase wire, the other end is suspended. One hand pinch the tip of the black pen, the other hand holding the red pen, so that the tip of the wire along the insulation layer slowly from the end of the phase line connected to start moving backward. When the multimeter's voltage reading suddenly becomes small (equivalent to one-tenth of the original reading), from here back to the 15CM is the break point of the wire.
With this method only need to destroy a point of the wire to solve the problem, is not very convenient ah. This method can also be used to detect the break point of the electric blanket.
2. Use a multimeter to detect short-circuit faults in the circuit.
When the family's circuit has broken wires or circuit aging caused by a short circuit between the firewire and zero line, generally this short circuit point is difficult to determine where, then the resistance method with a multimeter can be easily found. After the line short circuit, you should disconnect the main switch, unplug all electrical appliances. The multimeter is placed in the resistance file, the two pens are connected to the fire line and zero line, if the resistance value is zero or very small can be concluded that the short circuit. It is necessary to measure the resistance value between the fire wire and the zero wire section by section, if necessary, you can cut off a section of wire to determine the short-circuit point.
Digital multimeter working principle
The basic circuit of the digital multimeter is a header circuit, which completes the basic function of the input DC voltage (analogue) quantification, and output; other functions generally need to increase the external circuit. Now the multimeter chip, its integration is getting higher and higher, less and less peripheral circuitry, so there are advantages and disadvantages. Advantages: high integration, simple external circuitry, component quality problems caused by quality failures will be much less; disadvantages: chip a bad, replacement cost is high and troublesome, and sometimes the money to replace a chip, can buy another instrument, so the general bad have to scrap.
