pounds 12k for TV history.
Inventor John Logie Baird's receiver is almost 80 years old and originally sold for just pounds 5.
As early TV sets had no internal receiver, the device was hooked up to a "televisor" to watch broadcasts available between 1929 and 1932.
Fewer than 100 were built and sellers Bonhams revealed this was the first to be auctioned.
The museum's Alison Taubman said: "This is an important addition to an already significant collection of Baird material."