I believe that headphones are already a necessity in everyone's life. It is extremely pleasant to listen to songs while at home, in the office, or in headphones. Without affecting others, you can freely immerse yourself in your music world. However, does anyone know what the earliest headphones look like? Please follow the Xiaobian to see the evolution of headphones! In the 1880s, the world's first pair of headphones was born, but it has no relationship with music. It is born for communication. Use a few pounds of headphones on your shoulders, just like putting a speaker on your shoulders. By 1895, people began to listen to music on their home headphones. However, this headset looks like a face-lifting device that is used by girls to face-lifting. Is there a wood? During the year, Nathaniel Baldwin built the first modern headphones in his kitchen and sold them to the US Navy. This pair of headphones has also begun to look like a modern headset. And Baldwin may only care about making money and forget to apply for a patent. The world's first dynamic headphone DT-48 made by Beyerdynamic is undoubtedly a milestone in the history of headphones. AKG, which is focused on the film equipment industry, jumped out of the line this year and began to turn to audio-visual equipment, and designed and produced its first modern headset K120. John C. Koss built the world's first stereo headset, the Koss SP-3, and in the next decade it dominated the headset market. The world's first electrostatic headset, the SR-1, appeared in Tokyo, Japan, and was launched by Stax. Compared to moving coil headphones, electrostatic headphones sound more delicate and less distorted. Koss introduced the first American-made electrostatic headset ESP-6 ten years after the launch of its first stereo headset. The phone weighs 0.9 kilograms, at least much better than the previous shoulder-mounted speakers. Speaking of the big events in the history of headphones, I have to mention the appearance of Sony Walkman. Suddenly, the spring breeze comes, the streets are full of young people wearing headphones, fashion and proud! Men and women don't have to worry about haircuts being messed up with bulky headphones, but the peak of earbuds came after Jobs introduced the iPod a few years later. Earphones don't isolate the outside world well, and if you want to protect your hair, use Sony's rear-mounted headphones. Bose's anti-noise headset QuietComfort for the general public allows users to enjoy their music world in front of roaring airplanes or noisy TVs. The emergence of the iPod has subverted the entire music world, and people who walk around the house can see a white headphone cord hanging around their ears. According to statistics, since 2001, 300 million pairs of headphones have been sold along with the iPod. The playboy Dr. Dre, the record company Interscope Geffen A&M chairman Jimmy Iovine and the magic sound headset Monster jointly launched the Beats by Dre headset, which quickly occupied half of the headset market. At that time, almost every NBA player hangs Beats by Dre from the car to the lounge. In addition to listening to music, today's headphones have to lead the fashion trend. Take a look at Lil Wayne's bling bling Beats by Dre headphones, which are said to be worth millions of dollars!
As LCD display in YFJ company that we usually use it to military grade battery ,especially Lithium-ion batteries ,for these battery applications ,we have obvious advantage is that we focus more on shor circuit protection which we follow the US military standard.
Short circuit protection:The following test shall be performed. Charge batteriesas specified in ; use of 4.6.3 is permitted. Measure and record the OCV. Short each battery across all the positive and negative terminals with a total external resistance not greater than 50 milliohms. After one hour remove the short from across the terminals. Measure and record the OCV. Stabilize batteries at the normal conditions of 4.3.1 for not less than 2 hours. Chargebatteries in accordance with 4.6; use of 4.6.3 is permitted. Stabilize batteries at normal conditions for not less than 2 hours, then discharge the battery in accordance with 4.7.2.3. The battery shall meet the requirements of 3.7.2.3.
Li-Ion Battery With Lcd Display
Charge voltage: 16.8V
Nominal voltage : 14.8V
(4S7P)
Initial impedance : 120mΩ
Nominal capacity: 19.6Ah
Minimum capacity: 19.4Ah
Communication methods : SMBUS data communication
Electricity quantity show: LCD Electricity quantity show
Charge current: Standard Charging::0.2C5A (3.9A)
Rapid charge: 0.5C5A C(9.8A) Max
Standard Charging method : 3.9A(0.2C5A) CC(constant current)charge
to 16.8V,then CV(constant voltage 16.8V)charge till charge current decline to
≤196mA(≈0.01C5A)
Charging
time:Standard Charging: 6.5hours(Ref.)
Rapid charge: 3.5 hours(Ref.)
Max.discharge current: 9.8A(0.5C5A)
Discharge cut-off voltage: 10.0V
Cycle life (0.2C5A/0.2C5A) : 500 items,≧80%DOD;
300 times,≧80%DOD
Operating
temperature : Charging: 0℃~45℃
Discharging:-20℃~+60℃
Li-ion Battery With LCD Display Li-Ion Battery With Lcd Display,Battery Charger With Lcd Display,Battery Pack With Lcd Display,Rechargeable Battery Pack With Lcd Display YFJ TECHNOLOGY (HK) CO.,LIMITED , http://www.yfjpower.com
Headphone history history headphones comprehensive review
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