Valve-operated radio, 1955.
© Science Museum / Science & Society Picture Library
A portable broadcast receiver, type R55, made by Roberts Radio. This valve-operated radio looks like a transistor radio, and is typical of more expensive 1950s domestic radio receivers. Portable valve radios suffered from the fact that their battery demands made them expensive to run. In 1948, William Shockley (1910-1989) invented the transistor, and in the 1950s, transistors began to replace thermionic valves in radio receivers, allowing much smaller portable radios to be produced.