A batteryless radio is a radio receiver which does not require the use of a

battery Battery most often refers to: * Electric battery, a device that provides electrical power * Battery (crime), a crime involving unlawful physical contact Battery may also refer to: Energy source *Automotive battery, a device to provide power t ...

to provide it with electrical power. Originally this referred to units which could be used directly by AC mains supply (mains radio); it can also refer to units which do not require a power source at all, except for the power that they receive from radio waves.

History

The line-operated vacuum tube receiver was invented in 1925 by

Edward S. Rogers, Sr. Edward Samuel Rogers Sr. (June 21, 1900 – May 6, 1939) was a Canadian inventor and pioneer in the radio industry who founded the Rogers Vacuum Tube Company and the CFRB radio station in Toronto, Ontario. His only child, Edward S. Rogers Jr. ...

The unit operated with 5 Rogers AC

vacuum tube A vacuum tube, electron tube, valve (British usage), or tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric potential difference has been applied. The type known as ...

s and the Rogers Battery-Eliminator Power Unit (power supply). This unit was later marketed for $120 as "Type 120". He established the

Toronto Toronto ( ; or ) is the capital city of the Canadian province of Ontario. With a recorded population of 2,794,356 in 2021, it is the most populous city in Canada and the fourth most populous city in North America. The city is the anch ...

station

CFRB CFRB (1010 kHz) is a commercial AM radio station in Toronto, Ontario, Canada. It is owned by Bell Media and carries a News/Talk radio format. Its studios and offices are in the Entertainment District at 250 Richmond Street West. CFRB is a ...

(an abbreviation of ''Canada's First Rogers Batteryless'') to promote sales of the product. Batteryless radios were not introduced into the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

until May 1926 and then into

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...

in 1927. Crystal radio receivers are a very simple kind of batteryless radio receiver. They do not need a battery or power source, except for the power that they receive from radio waves using their long outdoor wire antenna.

Thermoelectricity The thermoelectric effect is the direct conversion of temperature differences to electric voltage and vice versa via a thermocouple. A thermoelectric device creates a voltage when there is a different temperature on each side. Conversely, when ...

was widely used in the remote parts of the

Soviet Union The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...

from the 1920s to power radios. The equipment comprised some bi-metal rods (

thermocouple A thermocouple, also known as a "thermoelectrical thermometer", is an electrical device consisting of two dissimilar electrical conductors forming an electrical junction. A thermocouple produces a temperature-dependent voltage as a result of th ...

s), one end of which could be inserted into the fireplace to get hot with the other end left out in the cold. After the

Second World War World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposi ...

kerosene Kerosene, paraffin, or lamp oil is a combustible hydrocarbon liquid which is derived from petroleum. It is widely used as a fuel in aviation as well as households. Its name derives from el, κηρός (''keros'') meaning "wax", and was regi ...

radios were made in

Moscow Moscow ( , US chiefly ; rus, links=no, Москва, r=Moskva, p=mɐskˈva, a=Москва.ogg) is the capital and largest city of Russia. The city stands on the Moskva River in Central Russia, with a population estimated at 13.0 millio ...

for use in rural areas. These all-wave radios were powered by the kerosene lamp hanging above them. A group of

s was heated internally to by the flame. Fins cooled the outside to about . The temperature differential generated enough current to operate the low-drain receiver. Foot-operated radio or pedal radio was once used in Australia. Other ways of achieving the same function are

clockwork radio Human power is work or energy that is produced from the human body. It can also refer to the power (rate of work per time) of a human. Power comes primarily from muscles, but body heat is also used to do work like warming shelters, food, or othe ...

, hand crank radio and solar radio, especially for the

Royal Flying Doctor Service The Royal Flying Doctor Service (RFDS), commonly known as the Flying Doctor, is an air medical service in Australia. It is a non-profit organisation that provides emergency and primary health care services for those living in rural, remote an ...

and

School of the Air School of the Air is a generic term for correspondence schools catering for the primary and early secondary education of children in remote and outback Australia where some or all classes were historically conducted by radio, although this is n ...

.Hand Crank and Solar Powered Emergency Radios
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Carrier-powered radio

A carrier-powered radio is a batteryless radio which "leeches" its power from the incoming electromagnetic wave. A simple circuit (very similar to a crystal set) rectifies the incoming signal and this DC current is then used to power a small transistor amplifier. Typically a strong local station is tuned in to provide power, leaving the listener free to listen to weaker and more distant stations.

References

{{reflist

External links

Museum of thermoelectric generators
Thermodynamics Electricity Types of radios

History

Carrier-powered radio

See also

References

External links