Principles and Maintenance of Automotive Circuits
One, understand the general sequence of automotive circuit diagrams
1 . The power supply is limited to the wires of the electric fuse or switch is the common front of the electric equipment. It is generally drawn on the upper part of the circuit diagram in the circuit schematic diagram.
2 . The circuit diagram of the standard drawing method, the contact of the switch is in the zero position or dynamic. That is, the switch is in the off state or the relay coil is in the non-energized state. The on and off of the elements with switching characteristics such as transistors and thyristors depends on the full house situation.
3. The characteristics of the automobile circuit are dual power supply, single wire system, each electrical appliance is connected in parallel with each other, and relays and switches are connected in series in the circuit.
4. Most of the power-consuming equipment passes through the fuse and is cherished by the fuse.
5. The whole vehicle circuit is composed of several independent circuits according to the effectiveness and working principle. This can solve the problem of the huge and chaotic circuit of the whole vehicle and the difficult analysis of the title. Nowadays, the entire automobile circuit is generally drawn according to the various circuit layouts, such as the power supply system, the starting system, the ignition system, the lighting system, the signal system, etc. These unit circuits have their own characteristics. The principle is thoroughly understood, and it is easy to understand the circuit of the whole car.
2. Responsible for reading circle notes
Responsible for reading the legend, understanding the title and technical type of the circuit diagram, and want to know how long it will take to learn car maintenance. Understand the meaning of graphic symbols and the correlation between equipment components and graphic symbols one by one, so that you can quickly and accurately recognize pictures.
Three, driving the circuit
In electricity, the circuit is the most basic, most important, and simplest concept. Any complete circuit is composed of power supply, electrical appliances, switches, wires, etc. Regarding the DC circuit, the current always goes from the positive pole of the power supply, and reaches the consumer through wires, fuses, and switches. Then go through the wire (or ground) and return to the negative pole of the same power source. In this process, only one link needs to be faulty, and this circuit will not be accurate and useful. For example: How long does it take to learn how to repair a car from the positive pole of the power supply? After a certain electrical appliance (or another electrical appliance), it finally returns to the positive pole of the same power source. Since the potential difference (voltage) of the power source is only between the positive and negative poles of the power source, the same electrode of the power source is equipotential. There is no voltage. This kind of "from positive to positive" approach does not produce current. In the car circuit. Generators and batteries are both power sources. When looking for a circuit, they should not be confused and cannot be driven from the positive pole of a power source. After going through a number of electrical equipment, return to the negative pole of another power supply, this way. No real path will be formed, and no current will appear. Take a look at car circuit repair training. So it must be exaggerated. The loop refers to driving from the positive pole of a power source, passing through the electrical appliances, and returning to the negative pole of the same power source.