The Jet Engine came along in the 1930's
Tea bags were introduced and sold in stores.
The BBC broadcasted a wider range of television programs until the war in 1939 and TV stays off the air until 1946. Much of the tech. staff were used during this time for the development of radar for the war effort.
Electric Razor- 1931 by Jacob Schick- USA
Electron Microscope-1933 by Ernst Ruska- Germany
Helicopter- 1936 by Heinrich Focke- Germany
Jet Engine- 1930 by Frank Whittle- England