D model is 1 battery, which is widely used. Flashlights are the same for civilian use, military use and ignition. The standard D (flat head) battery is 59.0 0.5 mm high and 32.3 0.2 mm in diameter.
Type C: No.2 battery, widely used in flashlights and audio-visual equipment. The standard size is 49.5 0.5 mm in height and 25.3 0.2 mm in diameter.
Type A battery is No.3 battery, which is generally used as a battery pack. The height of Type A battery is almost the same as that of No.2 battery, but the diameter is slightly smaller. The height of standard A (flat head) battery is 49.0 0.5 mm, and the diameter is16.8 0.2 mm. ..
AA battery is the 5th battery and the most common one. Electric shavers, electronic toys, digital devices and many AA rechargeable batteries are also used as battery packs.
AAA battery is commonly known as battery number seven. As shown in the figure below, battery 7 is a little smaller than battery 5. It is mostly used for remote control and other places with limited volume but low power consumption, and is mostly used for multi-section combination.
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Selection of battery
1. Buy battery products marked with "National Inspection Exemption" and "China Famous Brand" and local famous brand battery products. The quality of these products is guaranteed.
2, according to the requirements of electrical appliances, choose the appropriate battery type and size, and according to the size and characteristics of electrical power consumption, choose and buy batteries suitable for electrical appliances.
3. Pay attention to the production date and shelf life of the battery, and buy a battery (new battery) with good performance.
4, pay attention to check the appearance of the battery, should buy beautifully packaged, neat appearance, clean, no signs of leakage of battery.
5, pay attention to the battery logo, battery trademark should indicate the manufacturer's name, battery polarity, battery model, nominal voltage, trademark, etc. ; The sales package shall have the Chinese address, production date and shelf life, or indicate the effective period of the shelf life and the number of the implementation standard. Don't buy products without Chinese factory name, production date and shelf life, shelf life and implementation standards.
6. Because the mercury in the battery is harmful to the environment, in order to protect the environment, batteries marked with the words "no mercury", "0% mercury" and "no added mercury" should be selected when purchasing.
Baidu encyclopedia-battery