Loewe multiple valve radio receiver, late 1920s.
© Science Museum / Science & Society Picture Library
A radio which has two valves (one metallised and one plain),and four coils (two long wave and two medium wave). German engineer Siegmund Loewe (1885-1962) developed several vacuum tubes which included nearly all the components (resistors, capacitors and valves) needed to make a radio. The base of this compact receiver provides only variable capacitors and an interchangeable coil for tuning. Everything else is in the tube.