The 1 acts like a switch. It can turn electricity on or off, or it can amplify current. It is used for example in computers to store information or in stereo amplifiers to make the sound signal stronger. The 2 limits the flow of electricity and gives us the possibility to control the amount of current that is allowed to pass. The 3 collects electricity and releases it all in one quick burst , like for instance in cameras where a tiny battery can provide enough energy to fire the flashbulb .