A frequency converter includes a rectifier circuit and an inverter circuit. The input AC power is converted into DC voltage through the rectifier circuit and smoothing circuit. The difference between high-voltage and low-voltage electricity lies primarily in their applications. High-voltage electricity is used as a power source, while low-voltage electricity is used for information transmission. Specifically, they differ roughly as follows:
(1) Different communication frequencies
The frequency of high-voltage electricity is generally 50Hz (hertz), which is called "power frequency", meaning the frequency of industrial electricity. The frequency of low-voltage electricity is often high frequency or ultra-high frequency, measured in KHz (kilohertz) or MHz (megahertz).
(2) Different transmission methods
High-voltage electricity is transmitted via power lines, while low-voltage electricity can be transmitted via wired or wireless means. Radio waves are transmitted via electromagnetic waves.
(3) Different power, voltage and current magnitudes
High-voltage electrical power is measured in KW (kilowatt) or MW (megawatt), voltage in V (volt) or KV (kilovolt), and current in A (ampere) or kA (kiloampere); low-voltage electrical power is measured in W (watt) or mW (milliwatt), voltage in V (volt) or mV (millivolt), and current in mA (milliampere) or uA (microampere). Therefore, its circuit can be constructed using printed circuits or integrated circuits.
Of course, high-voltage electricity also includes high-frequency (hundreds of kHz) and medium-frequency devices, but these operate at higher voltages and currents. Similarly, flashlights and electric shavers, despite their low voltage, low power, and low current, are still considered high-voltage. Due to advancements in modern technology, low-voltage electricity has permeated the high-voltage field, as seen in power electronic devices and wireless remote controls. However, these can only be considered the low-voltage control portion of high-voltage electricity; they are still different from the controlled high-voltage electricity.
Electronics are generally divided into two parts: high-voltage (electrical power) and low-voltage (information). While related, they are distinct. High-voltage systems typically deal with energy (electricity), characterized by high voltage, high current, high power, and low frequency, primarily focusing on minimizing losses and improving efficiency. Low-voltage systems, on the other hand, primarily deal with information, i.e., information transmission and control, characterized by low voltage, low current, low power, and high frequency, primarily focusing on the quality of information transmission, such as fidelity, speed, reach, and reliability. Generally, low-voltage engineering includes television engineering, communication engineering, fire protection engineering, security engineering, video engineering, etc., and the comprehensive cabling engineering serving these projects. Low-voltage is defined in contrast to high-voltage. High-voltage = (380/220), high voltage is irrelevant.
In a power system, voltages below 36V are called safe voltages, voltages below 1kV are called low voltages, and voltages above 1kV are called high voltages. Lines directly supplying power to users are called distribution lines. For example, if the user's voltage is 380/220V, it is called a low-voltage distribution line, which is what is referred to as "high-voltage electricity" in home renovations (because it is the highest voltage used in homes). High-voltage electricity generally refers to AC voltages above 24V. For example, household lights and sockets operate at 110V~220V. Household electrical appliances such as lighting fixtures, electric water heaters, heaters, refrigerators, televisions, air conditioners, and audio equipment are all high-voltage electrical equipment.
Intelligent systems encompass building equipment monitoring systems, security systems, communication network systems, information network systems, automatic fire alarm systems, and fire-fighting linkage systems, forming a comprehensive system for centralized monitoring, control, and management. The wiring within a home, including the control or network systems for various data acquisition, control, management, and communication, is called intelligent wiring (also known as low-voltage wiring in home renovation). Low-voltage wiring generally refers to DC circuits or audio, video, network, and telephone lines, with DC voltage typically below 24V. Household electrical appliances such as telephones, computers, television signal inputs (cable TV lines), and audio equipment (output lines) are all considered low-voltage electrical equipment.
Conceptually, high-voltage and low-voltage electricity are generally easy to distinguish, mainly due to their different uses. High-voltage electricity is used as a power source, while low-voltage electricity is used for information transmission. Specifically, they differ roughly as follows:
(1) Different AC frequencies: The frequency of high-voltage electricity is generally 50Hz, called "power frequency", which is the frequency of industrial electricity; the frequency of low-voltage electricity is often high frequency or ultra-high frequency, measured in kilohertz (KHz) or megahertz (MHz).
(2) Different transmission methods
High-voltage electricity is transmitted via power lines, while low-voltage electricity can be transmitted via wired or wireless means, and radio waves are transmitted via electromagnetic waves.
(3) Differences in power, voltage, and current.
High-voltage electrical power is measured in kilowatts (KW) and megawatts (MW), voltage in volts (V) and kilovolts (KV), and current in amperes (A) and kiloamperes (KA); low-voltage electrical power is measured in watts (W) and milliwatts (mW), voltage in volts (V) and millivolts (mV), and current in milliamperes (mA) and microamperes (μA). Therefore, its circuits can be constructed using printed circuits or integrated circuits.
Of course, high-voltage electricity also includes high-frequency (several megahertz) and medium-frequency devices, but these operate at higher voltages and currents. Similarly, flashlights and electric shavers, despite their low voltage, low power, and low current, are still considered high-voltage. Due to advancements in modern technology, low-voltage electricity has permeated the high-voltage field, as seen in power electronic devices and wireless remote controls. However, these can only be considered low-voltage control components within high-voltage systems; they are still different from the controlled high-voltage electricity.
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