Learn about the advantages of Germanium Diodes
Diodes are a very important component of most alternative energy generating systems - for example in PV solar panels they are used to stop energy being radiated back out into the night sky from the batteries, and in wind turbine generators they are used to rectify AC into DC electricity.
Typical diodes are made of silicon because of its ease of processing and stability however they have one disadvantage: a silicon diode has a forward voltage drop of around 0.7 volts. Therefore in a Bridge Rectifier where the current passes through two diodes, the total forward voltage drop is 1.4 volts. This is very significant in low voltage systems. A Germanium Diode typically will have a forward voltage drop of 0.3 volts which means they are much more efficient. Older germanium diodes had a larger leakage of current at a reverse voltage, but now American Microsemiconductor supply a range of improved low leakage current germanium diodes. Diodes such as the most common 1N34A cost around 5 pence each.
An interesting article about the practical use of Germanium Diodes in a crystal radio set is here, and discusses the forward voltage drop of a selection of germanium diodes in real world testing. The OA47 came out tops with a forward voltage drop of under 250mV.
http://www.reuk.co.uk/Germanium-Diodes.htm
