The tiny switch that built the modern world: How the transistor changed everything
A new Wired explainer traces the lineage of electronic switches from 19th-century telegraph relays to the semiconductor devices that now power billions of global connections.
The transistor, invented at Bell Labs in 1947, has been described as perhaps the most important invention of the 20th century. A recent article in Wired details the history and mechanics of this pivotal component, arguing that modern digital infrastructure would be unrecognisable without it. The piece highlights that the transistor is the foundational technology for the computer revolution, enabling everything from personal computers to artificial intelligence.
To understand the significance of the transistor, the article traces the evolutionary path of electronic switches back to the 19th century. Electric relays, invented in 1835, were the first such devices, used in telegraph systems to manage signal resistance over long distances. These relays functioned as basic on-and-off switches, using a second electric current to flip a mechanical contact. While still widely used today in applications such as automotive systems, relays were limited by their mechanical nature and speed.
The next major development was the vacuum tube, invented around 1905. Unlike relays, vacuum tubes offered variable current control and faster switching speeds, which made early audio amplification and computing possible. However, these components came with significant drawbacks. They were fragile, power-hungry, and large in size. Early computers, such as ENIAC in 1945, relied on thousands of vacuum tubes, requiring massive cooling systems and full-time maintenance crews to replace burnt-out components.
The transistor solved these specific limitations by utilising semiconductors. Materials like silicon can switch between conducting and insulating states, allowing for a device that is smaller, more efficient, and more durable than its predecessors. By combining different types of semiconductors, engineers created a switch that could be controlled with much finer precision than a vacuum tube, without the need for mechanical parts or high heat generation.
The miniaturisation of this technology has been exponential. In the 1950s and 1960s, transistor radios contained only six to 10 of these components, replacing bulky floor-standing consoles. Today, the scale of integration is staggering. According to the Wired article, modern devices such as the iPhone 17 Pro contain up to 30 billion transistors.
This density of components is what allows for the complex processing power required by contemporary digital life. The article notes that cars, streaming services, and social media platforms all depend on this underlying technology. As the world continues to rely on digital infrastructure, the humble transistor remains the critical link between raw electricity and information.
