PWM dimming the LED load is in series with a MOS switch transistor, the anode of the LED string of a constant current power supply. A PWM signal is then applied to the gate of the MOS transistor to quickly switch the string of LEDs for dimming. In this article, we will briefly talk about the advantages and disadvantages of PWM dimming.
1. No chromatographic shift will occur. Because the LED always works between full-scale current and zero.
2, can have a very high dimming accuracy. Because the pulse waveform is fully controllable to very high precision, it is easy to achieve one-tenth of the accuracy.
3, can be combined with digital control technology to control. Because any number can be easily converted into a PWM signal.
4. Even if the light is dimmed in a wide range, no flicker will occur. Since the operating conditions of the constant current source (boost ratio or step-down ratio) are not changed, it is less likely that overheating will occur.
However, PWM pulse width dimming also has problems to be aware of. The first is the choice of pulse frequency: because the LED is in the fast switching state, if the operating frequency is very low, the human eye will feel flicker. In order to make full use of the visual residual phenomenon of the human eye, its operating frequency should be higher than 100 Hz, preferably 200 Hz.
The second is to eliminate the whistling caused by dimming. Although the human eye is not noticeable above 200 Hz, it is the range of human hearing until 20 kHz. At this time, it is possible to hear the sound of the silk. There are two ways to solve this problem. One is to increase the switching frequency to above 20 kHz and jump out of the human ear. However, too high a frequency can cause some problems, because the influence of various parasitic parameters will cause the pulse waveform (front and rear edges) to be distorted. This reduces the accuracy of dimming. Another method is to find out the sounding device and process it. In fact, the main sounding device is the ceramic capacitor at the output, because ceramic capacitors are usually made of high dielectric constant ceramics, which have piezoelectric properties. Under the action of a pulse of 200 Hz, mechanical vibration is generated and sounds. The solution is to use a tantalum capacitor instead. However, high-voltage tantalum capacitors are difficult to obtain, and the price is very expensive, which will increase some costs.
Litecoin (LTC) is a cryptocurrency created as a fork of Bitcoin in 2011. It uses a hashing algorithm called Scrypt that requires specifically designed mining software and hardware. It is minable, and continues to rank in the top cryptocurrencies for value and trading volume.
Litecoin mining is the process of validating transactions in the blockchain, closing the block, and opening a new one. Litecoin uses the proof-of-work consensus mechanism, which uses computational power to solve the nonce, which is part of the hash, that secures the block. The hash is the alphanumeric sequence of numbers that is encrypted by the hashing algorithm. When the nonce is solved, Litecoin is rewarded.
Litecoin mining became popular in 2011 when Charlie Lee, a software engineer at Google, announced its creation as a Bitcoin fork with modifications intended to help it scale more effectively.
Just like Bitcoin, it can be mined on computers using central processing units and graphics processing units. However, it isn't as profitable or competitive as purchasing an application-specific integrated circuit (ASIC) and joining a mining pool.
Ltc Asic Miner,Antminer L3 Plus Plus,Bitmain Antminer L3 Plus,Bitmain L3 Plus
Shenzhen YLHM Technology Co., Ltd. , https://www.apgelectrical.com