Graetz AG was a German

Germany

Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 manufacturer of petrol lamp

Kerosene lamp

The kerosene lamp is a type of lighting device that uses kerosene as a fuel. This article refers to kerosene lamps that have a wick and a tall glass chimney. Kerosene lanterns that have a wick and a glass globe are related to kerosene lamps and are included here as well...

s. In 1899 the company began to produce radio

Radio

Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...

 sets at its plant in Treptow

Treptow

Treptow is a former borough in the southeast of Berlin. It merged with Köpenick to form Treptow-Köpenick in 2001.-Geography:The district was composed by the localities of Alt-Treptow, Plänterwald, Baumschulenweg, Niederschöneweide, Johannisthal, Adlershof, Altglienicke and Bohnsdorf....

, Berlin

Berlin

Berlin is the capital city of Germany and is one of the 16 states of Germany. With a population of 3.45 million people, Berlin is Germany's largest city. It is the second most populous city proper and the seventh most populous urban area in the European Union...

. The company lent its name to an electrical circuit called the diode bridge, which is better known as the full-wave bridge rectifier. A drawing of this circuit attributed to Graetz, dated 1897, appears in a paper by Chattopadhyay.