In 1998, one of the first examples of distributing and selling media content through the mobile phone was the sale of ringtones by Radiolinja in Finland. Soon afterwards, other media content appeared, such as news, video games, jokes, horoscopes, TV content and advertising. Most early content for mobile phones tended to be copies of legacy media , such as banner advertisements or TV news highlight video clips. Recently, unique content for mobile phones has been emerging, from ringtones and ringback tones to mobisodes , video content that has been produced exclusively for mobile phones.
A typical, conventional lead-acid battery consists of a 6V pack, . the battery has 6 cells in it, with each cell having a capacity of 2 Volts (emf is equal to approximately V in each cell). The internal resistance depends on the maximum voltage that is currently flowing through the battery. In a fully charged Volt lead-acid battery, the internal resistance is about 10 milliohms. This very low resistance results in the high maximum current that the battery can produce. However, unlike the nickel-cadmium battery, it can only produce this current for a very limited amount of time (200 to 300 cycles), after which the current will begin to diminish and internal resistance will begin to increase. The resistance is also affected by the number of cells in the battery, . the more cells, the higher the joint internal resistance. The most common application of the lead-acid battery is the motorcar battery, also known as a lead-acid accumulator. This type of battery (usually 6V or 12V) uses a dynamo to recharge the battery and store energy while the car is turned off, so that it doesn't run flat.