Welcome to High Technology Week here at OPOD, where we will look at cool and exciting technology developments over the last hundred years. We start with this picture from around 1920 showing a woman listening to a radio over headphones. As you can see, radios were huge back in the day. The radios amplified the signal coming from the antenna using Vacuum Tubes. These tubes were big, expensive, got very hot, and did not last very long, but they did enable people to have radios in their homes. I have heard of many people who got radios in their homes even before electricity. Some ran the radios on "Wind Chargers", which were generators with a propeller, and spun by the wind. Others kept an extra car battery to run the radio. Then each day, they would swap the batteries between the car and the radio. Driving to work would then recharge the battery.