Ekco radio receiver, type AC85, with a black Bakelite case. When combined with a wood flour filler, phenol formaldehyde, known by its trade name 'Bakelite' after its inventor, Leo Baekeland, forms a useful mouldable plastic, with very good electrical insulating properties. It was the first plastic to be used for making radios. In 1917, Edward Howard Armstrong (1890-1954) developed the superheterodyne electronic circuit, which significantly improved the sensitivity and selectivity of radio receivers over a wide range of frequencies, making amplifier tuning unnecesary. This made the task of tuning the radio receiver to different stations much more simple and straightforward.
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