A batteryless radio is a

radio receiver In radio communications, a radio receiver, also known as a receiver, a wireless, or simply a radio, is an electronic device that receives radio waves and converts the information carried by them to a usable form. It is used with an antenna. T ...

which does not require the use of a battery to provide it with electrical power. Originally this referred to units which could be used directly by

AC mains supply Mains electricity or utility power, power grid, domestic power, and wall power, or in some parts of Canada as hydro, is a general-purpose alternating-current (AC) electric power supply. It is the form of electrical power that is delivered to h ...

(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. 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 voltage, potential difference has been applied. The type kn ...

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 Provinces and territories of Canada, Canadian province of Ontario. With a recorded population of 2,794,356 in 2021, it is the List of the largest municipalities in Canada by population, most pop ...

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 c ...

(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 U.S. state, states, a Washington, D.C., federal district, five ma ...

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 enti ...

in 1927.

Crystal radio A crystal radio receiver, also called a crystal set, is a simple radio receiver, popular in the early days of radio. It uses only the power of the received radio signal to produce sound, needing no external power. It is named for its most impo ...

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, whe ...

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 Bimetal refers to an object that is composed of two separate metals joined together. Instead of being a mixture of two or more metals, like alloys, bimetallic objects consist of layers of different metals. Trimetal and tetrametal refer to objects c ...

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 World War II by country, vast majority of the world's countries—including all of the great power ...

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 reg ...

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 million ...

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, hand

crank Crank may refer to: Mechanisms * Crank (mechanism), in mechanical engineering, a bent portion of an axle or shaft, or an arm keyed at right angles to the end of a shaft, by which motion is imparted to or received from it * Crankset, the compone ...

radio and

solar Solar may refer to: Astronomy * Of or relating to the Sun ** Solar telescope, a special purpose telescope used to observe the Sun ** A device that utilizes solar energy (e.g. "solar panels") ** Solar calendar, a calendar whose dates indicate t ...

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 a ...

and School of the Air.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