Transistor radios are small, portable devices that use transistors to amplify radio signals. They were first developed in the late 1940s and became popular in the 1950s and 1960s. These radios allowed people to listen to music and news on the go, revolutionizing how we consume audio content. The invention of the transistor, a key component in these radios, made them more efficient and compact compared to earlier vacuum tube radios. Transistor radios typically run on batteries, making them ideal for outdoor activities and travel. They played a significant role in the rise of personal entertainment devices.