They are used to steer light through circuits in the same way that electronic circuits direct electric current.
From the newscientist.com
Just as his most famous legacy, the incandescent light bulb, heads for extinction, his other great passion, direct electric current, is set to boom.
From the newscientist.com
The dynamo uses rotating coils of wire and magnetic fields to convert mechanical rotation into a pulsing direct electric current through Faraday's law of induction.
From the en.wikipedia.org
All electronic devices have to convert the alternating current, AC, that comes out of electric sockets into direct current, DC.
From the investors.com
Following Sturgeon's work, a commutator-type direct-current electric motor made with the intention of commercial use was built by Americans Emily and Thomas Davenport and patented in 1837.
From the en.wikipedia.org
At first, all electric railways used direct current but, in 1904, the Stubaital Line in Austria opened with alternating current.
From the en.wikipedia.org
Because of the significant advantages of alternating current over direct current in transforming and transmission, electric power distribution is nearly all alternating current today.
From the en.wikipedia.org
While not originally designed for the purpose, it was discovered that a dynamo can act as an electric motor when supplied with direct current from a battery or another dynamo.
From the en.wikipedia.org
Proton came up with a product that is the direct opposite of a fuel cell, which converts hydrogen to electric current and water.