What is the difference between high frequency and low frequency of power switch

1. The characteristics are different.

High frequency is a high-frequency and induction heating technology, which currently has the highest heating efficiency and fastest speed for metal materials, and has low consumption and environmental protection. It has been widely used in all walks of life in the heat processing, heat treatment, hot assembly, welding, smelting and other processes of metal materials.

High-power transmitters with low-frequency transmitting antennas require a lot of space, causing controversy in the United States and Europe for fear of exposure to high-power radio waves.

May have an impact on health.

2. The functions are different.

High frequency can not only heat the workpiece as a whole, but also heat the workpiece locally; It can realize the deep heat permeability of the workpiece, or only the surface and surface layer can be heated intensively; It can not only directly heat metal materials, but also indirect heating of non-metallic materials.

Low Frequency (Low Frequency) or LF is the -300 kHz designated by the ITU as a radio frequency in the range (RF) of kilohertz (KHz). Its wavelengths range from ten kilometers to one kilometer and are also known as kilometer bands or kilometer waves.

3. The role is different.

Induced current for high frequency.

A surface heat treatment process that heats the workpiece locally.

This heat treatment process is commonly used for surface quenching, but also for local annealing or tempering, and sometimes for integral quenching and tempering.

Low-frequency waves can also pass through from the ionosphere.

Reflection (the actual mechanism being one of refractions) occasionally propagates over long distances, although this method called skywave or "jump" propagation is not as common as at higher frequencies. Reflection occurs in the ionosphere, layer E or layer. Skywave signals can be detected at distances of more than 300 kilometers (190 miles) from the transmitting antenna.

1. Harm to human health:

Low-frequency voltage can endanger the life safety of the human body. High-frequency voltage has little damage to the human body. The high-frequency and low-voltage standard generally refers to the voltage standard with a voltage of 1 V 0 1 (or 0 2) V.

The voltage standard for this range is important for determining metrics such as receiver sensitivity and native noise. Electromagnetic radiation acting on the human body produces a series of biological effects.

The frequency band of 150 to 1200 MHz can penetrate more than 2 centimeters into the human body, stimulate the deep cells of the body, cause them to rub against each other to generate heat, and interfere with the body's own biocurrent.

Low-frequency voltages are not life-threatening to the human body only when they are below the safe voltage. When the voltage is higher than the safe voltage, it can cause electric shock and even kill people. The AC voltage higher than 1 trillion cycles will cause little harm to the human body.

2. The distance of the sensing distance:

The induction distance of the high-frequency card is farther, the low-frequency card is relatively close, the two radiation distances are different, like the high-frequency in the parking factory, you don't need to take it out to brush, the car has not yet arrived and opened according to the frequency and distance of the different high and low distances, the induction distance of the high-frequency card is farther, like the parking plant with the ultra-high frequency card, the car has not yet arrived] can be inducted and automatically opened.

The low-frequency card such as the forbidden card and the bus card have a short sensing distance, and they need to be close to 1cm to sense.

3. The difference between signal changes:

According to the spectrum allocation table developed by the Institute of Electrical and Electronics Engineers (IEEE), the low frequency is 30 300 kHz, the intermediate frequency is 300 3000 kHz, the high frequency frequency is 3 30 MHz, the frequency range is 30 300 MHz is VHF, and the frequency range is 30 1000 MHz is UHF. Compared with low-frequency signals, high-frequency signals change very quickly and have abrupt changes; Low-frequency signals change slowly and the waveform is smooth.

The power supply is not the same as the signal, and the voltage provided by the power strip is generally 0 (DC power) or 50Hz (AC power). The signal can be said to be high frequency or low frequency (or other frequency), and the power board is not easy to say, because it is only used to supply power, and the frequency is very low, and if you must say it, it is only low frequency.

Encyclopedia - high-frequency switching power supply.

Encyclopedia – Low Frequency.

1. High level refers to the high voltage opposite the low level, is a term in electrical engineering. In the logic level, the input of the logic gate is guaranteed to be the minimum input high allowed when the input level is high, and the input level is considered high when the input level is higher than the input high voltage (VIH).

2. Input low level (vil).: Ensure that the input of the logic gate is the maximum allowable input low when it is low, and when the input level is lower than vil, the input level is considered low. In digital logic circuits, a low level represents 0 and a high level represents a 1.

Generally, the low level is 0 and the high level is.

Related information

1. The high and low levels marked on the controller are brakes, and the high level is generally specified as more than 5V, and the low level is about 0V.

2. The voltage value on different circuits is not the same, if it is a digital circuit with 5V power supply, the high level is 5V, or close to 5V. Low is 'none', which is 0V or close to 0V.

3. The high level of the controller is on, and the low level is control.

High and low levels are also called high and low potentials The potential means the voltage to the ground and the voltage is relative to the potential of the two points, and the voltage to the ground is called the potential For example, the potential of point A and point B is 12V and 5V refers to their voltage to the ground, while the voltage of A relative to B is 12-5=7V, and the voltage of B relative to A is 5-12=-7VVoltage is a relative concept. The high and low levels are more meaningful in the number of electricity.

Usually the voltage of 0 is called low, and it is customary to call it"0"It's called high. called"1"If the voltage of the digital chip in a digital circuit is not within these ranges, it can cause logic errors. Ideally, high corresponds to +5V and low corresponds to 0V.

The high level in the electronic circuit is the state of high voltage, which is generally recorded as 1The low level in the electronic circuit is the state of low voltage, which is generally recorded as 0

High frequency and low frequency are relative concepts and absolute concepts1, to say that it is a relative concept:

Is it low or high? It is estimated that few people would say that it is low frequency. Isn't that an absolute concept?

No, in fact, when we say that it is high frequency, we already have a comparison in mind, for example, it may be because we often engage in audio or radio frequency.

If you've been working in the microwave field or optical communications, would you still think it's high frequency?

Admittedly, many of the problems may not have been encountered by you when you were 100 megabytes. We certainly have reason to say that it is high frequency, isn't it higher than 100 megabytes? In any case, the mind is still making comparisons.

Because of this, it's generally best for us not to say that I have a high-frequency problem that can't be solved, please ask for help from a certain hero! It's just to say that I have a specific problem in that frequency range, which is not clear there, and needs help.

2. To say that it is an absolute concept is also just a convention.

The frequencies are divided according to the regulations so that there is a professional language of communication:

Ultra-low frequency: Very low frequency: 300-3000Hz (audio).

Very low frequency: 3-300kHz

Long wave: 30-300kHz

Medium wave: 300-3000kHz

Shortwave: 3-30 megabytes.

VHF: 30-300 megabytes.

UHF: 300-3000 megabytes.

UHF: 3-30g

Very high frequency: 30-300g

Far infrared: 300 3000g

If you look at it, you'll know that there are a lot of answers!

High-frequency circuits: basically composed of passive components, active components, and passive networks. The frequency characteristics of components used in high-frequency circuits are different from those used in low-frequency circuits.

The passive linear components in high-frequency circuits are mainly resistors, capacitors, and inductors.

Low-frequency circuit: Low-frequency circuit can be understood as a centralized parameter circuit, that is to say, the wavelength of the electromagnetic wave transmitted in the wire is much larger than the size of the circuit components, and the electromagnetic wave propagates in the wire in the form of traveling waves. There are a wide variety of circuit laws that are satisfied in a centralized parametric circuit, and most circuit books talk about this kind of circuit.

The oscillation frequency of high-frequency switching power supply is generally tens of kHz, which is relative to the low frequency of ordinary 50Hz.

"High frequency" is a higher frequency, refers to the number of oscillations per second, in the case of TL494, a special chip for high-frequency switching power supply, its benchmark oscillation frequency is 25kHz, and the frequency is 500 times higher than the traditional 50Hz power supply. High-frequency switching power supplies have many advantages:

1. Small size and light weight. The old-fashioned 100-watt electrical appliances weigh a few pounds in the large power transformer of the power supply part alone, which occupies a large position in the chassis. The switching power supply is only a few hundred grams, and the palm is a small piece.

2. Save materials. The switching power supply saves a lot of copper and iron.

3. Stable and reliable. The switching power supply has multiple protection measures, and the traditional power supply is basically a fuse.

4. The voltage adjustment range is wide, and it is easy to achieve a wide range of voltage adjustment, which is incomparable with the traditional power supply.

5. High energy efficiency ratio of switching power supply.

6. The switching power supply eliminates the 50-week AC sound that the traditional power supply hates.

Switching power supplies have so many advantages that they have become more and more widely used to gradually replace traditional power supplies.

The high-frequency switching power supply has strong penetration and good adhesion, which can effectively improve the deposition speed of the coating; Flexible to use and simple to operate; Complete protection functions; Scalable. For details, please visit the official website of Taixing to understand!