Cat whisker detector

The cat whisker detector, also known as a crystal detector, was a pivotal component in early radio receivers. Invented in the early 20th century, it utilized a thin wire (the “whisker”) to make contact with a crystalline mineral, typically galena (lead sulfide). This arrangement formed a primitive semiconductor junction, capable of rectifying radio frequency signals to produce audible sound. The cat whisker detector was a key element in crystal radios, which were popular among early amateur radio enthusiasts for their simplicity and effectiveness without requiring an external power source. This innovation helped lay the foundation for modern semiconductor technology and the development of more advanced radio receivers.