Ekco 'Mains Drive', three-valve radio receiver, 1929.
© Science Museum / Science & Society Picture Library
By the late 1920s, with one household in three conected to mains electricity, all-electric radio sets were becoming increasingly popular. This particular model, manufactured by E K Cole and Co Ltd, was available in both AC and DC versions. It features single-knob tuning, the second dial being the 'reaction'control.