Solid-state rectifier from the Philips Million-Volt Accelerator, 1937.

UNITED KINGDOM - OCTOBER 09: This solid-state rectifier is from the voltage doubler stack of the Philips Million-Volt Accelerator, installed at the Cavendish Laboratory, Cambridge, in 1937. The rectifiers pass the electric charge into the accelerator itself. The Cavendish Laboratory substituted solid-state rectifiers for the tube rectifiers originally supplied with the accelerator. The stack generates the electric field used to accelerate particles such as protons and electrons during experiments using the accelerator. (Photo by SSPL/Getty Images)