It is the simplest to determine polarity of a wire by designations on a source of tension to which it is connected. However such opportunity is not always available. It can be the wires which are going out of the charger for automobile accumulators, conclusions of dynamic loudspeakers, food wires in the autoradio tape recorder. Sometimes it is necessary to learn which of several network wires phase, and what zero or to ring out the cable stretched from one room in another. In each case there is the solution of this question.
It is required to you
- multimeter, the food battery on 3 volts, the indicator screw-driver, a prozvonochny wire.
Instruction
1. For determination of polarity of the wires which are going out of the charger include a multimeter in the mode of measurement of constant tension to 20 volts, (negative) insert a black wire into COM nest, and red (positive) – in VΩmA nest. Connect probes to terminals of the charger and turn on it. If on the display of a multimeter there was a sign "minus", the polarity of connection means opposite, that is the red probe is connected to the negative terminal, and black - to the positive terminal of the charger. In case of lack of the sign "minus" of the terminal correspond to the probes connected to them.
2. For check of polarity of loudspeakers quickly concern its conclusions wires from the battery on 3 volts. At the movement of the diffuser of the loudspeaker outside the polarity of terminals of the loudspeaker corresponds to polarity of the battery. At the movement inside the polarity of conclusions of the loudspeaker is opposite to polarity of the battery.
3. It is easy to distinguish food wires in branded autoradio tape recorders on color which constantly corresponds to the wire. Black color at the wire connected to the weight or general "minus" of food, a red wire - "plus" of food is connected to the ignition lock, the yellow wire belongs to food "plus" too, is only connected to the accumulator. Anyway the wire with the safety lock is "power plus" of food.
4. When replacing the faulty switch there is not always an opportunity to cut off power the house or the apartment. In this case will help to define a phase (dangerous) wire the indicator screw-driver. It will help also when carrying out any repair work you came across an unknown wire.
5. For cable pro-calls with veins identical by sight include a multimeter in the mode of measurement of small resistance. In a case pro-calls of an alarm wire as the general prozvonochny wire it is possible to use the metal screen of a cable. On the one side of a cable connect the studied wire to the screen, and on the other hand connect the black probe to a braid and concerning serially wires, find the wire closed on the screen.