A DC power supply is a device that maintains a constant voltage and current in a circuit. Such as dry batteries, storage batteries, DC generators, etc.
There are many types of DC power supplies. In different types of DC power supplies, the nature of non-static forces is different, and the process of energy conversion is also different. In chemical batteries (such as dry batteries, accumulators, etc.), non-static forces are the chemical action associated with the dissolution and deposition of ions. When a chemical battery is discharged, chemical energy is converted into electrical energy and Joule heat. In thermocouples (semiconductor thermocouples), non-static forces are diffusive effects associated with temperature differences and electron concentration differences. When a temperature difference power supply provides power to an electrical circuit, thermal energy is partially converted into electrical energy. In DC generators, non-static forces are electromagnetic induction. When DC generators are powered, mechanical energy is converted into electrical energy and Joule heat. In photovoltaic cells, non-static forces are a function of the photovoltaic effect. When photovoltaic cells are powered, light energy is converted into electrical energy and Joule heat.
AC power is a modern word and is a proper noun. It refers to the plug and socket refers to the device used to connect the AC power provided by the city power supply to the household appliances and portable small devices.
Household AC power plugs and sockets refer to devices that are used to connect AC power provided by the city electricity, and to power household appliances and portable small devices.
The power plug has a male connector protruding in the shape of a rod or a copper plate, and is physically inserted into a female connector-type power socket with a slot or a recess. The plug generally has a live wire (shorter hole), a neutral wire connector (longer hole), and some have a grounding connector (central round hole). There are many types of plugs that do not specifically distinguish between live and neutral wires, and some connectors have multiple live wires. These connectors may be plated with copper, tin, nickel
The power socket is a female connector with a slot or a recess, which is used to insert a power plug with a stick or copper plate shape to conduct electricity to the appliance through the plug. Generally, sockets are designed so that plugs of different specifications cannot be inserted, and some sockets will have rod-shaped protrusions to match the recesses on the plugs.
Alternating current changes according to a sinusoidal curve. Due to the alternator, during the power generation process, multiple pairs of magnetic poles are evenly distributed on a circle at a certain angle, so that during the power generation process, when each magnetic pole cuts the magnetic field lines, they are complementary, so It can constantly generate a stable current; the frequency of alternating current is generally 50 Hz, that is, it changes 50 times per second, of course, there are other frequencies.
DC does not change in a sine curve. There is no change in frequency.
The most intuitive difference between AC and DC is that the direction changes; the direction of the DC current does not change at any time, but the size may change; the most special DC is a stable current that does not change in size and direction. The so-called alternating current is that the current flows alternately, and its direction changes alternately. The most common is civilian electricity. It is a sine (cosine) AC current. Square wave currents are common in electrical microelectronic circuits.
The electric shock person is the so-called electric shock, which means that the electric current forms a loop through the human body and reaches a certain intensity. The key problem is to form a loop and the voltage is within a certain range. In order for the body to feel charged, the current must have a certain intensity. Generally, the current passed by the human body is not greater than 30mA, and there is no danger to life.
Generally, the positive and negative poles of direct current are not grounded. At this time, you should hold one of the poles and the other pole is insulated. If it does not form a loop, you will not get an electric shock. Because there is a capacitive effect between the human body and the electrodes, if the voltage is too high, it will still get an electric shock.
General AC power refers to a 220 / 380V system, which uses a neutral point (transformer) grounding system, which is the neutral grounding. At this time, if the human body touches the phase wire (fire wire), it will form a loop through the earth and the neutral wire, and the current flowing through the human body will be far greater than 30mA, which will cause an electric shock.
Another note: no matter what electricity, as long as the current flowing through the human body is not large, you will not get an electric shock.