Although a batteryless radio is technically one that doesn’t require batteries it could still require power from the power socket in your home. When most people think about batteryless radios they are actually thinking about self powering radios.
There are a number of different types of these self powered radios. Many of these were around long before Trevor Baylis had the idea of creating his hand crank wind up radio.
Crystal Radios
Crystal radios are very simple types of self powering radio receiver. These do not require any form of power as they get all the power they need to operate from the radio waves. With these units a long antenna must be used. Also the sound produced is very quiet unless batteries or another source of power is used to amplify the radio waves.
Thermoelectricity
Electricity can be generated from a temperature difference by using thermocouples. These are made by bi-metal rods where one end gets hot and the other gets cold.
Thermoelectric radios were extremely popular in the rural areas of Russia. These radios are powered by a kerosene lamp to generate the heat and a heat sync on the side of the radio provides the temperature difference.
Solar Power
Solar power is a form of renewable electricity which has been used for a number of different purposes. Solar panels have found their way onto calculators and even cars. Some solar powered radios have been created as a way to generate electricity to power the radio without needing batteries or power.
These will typically have to be used outdoors in strong sunlight in order to generate enough power. Most have batteries which can be charged up by leaving the radio out in the sun.
Pedal Radio
Pedal radios have been used in Australia in the past and these us a very similar mechanism to the hand crank radios we will look at next.
