Stretching wire generates current
“The flexible charge pump offers yet another option for converting mechanical energy into electrical energy,” says Zhong Lin Wang, director of the Center for Nanostructure Characterization at the Georgia Institute of Technology. The generator can produce an oscillating output voltage of up to 45 millivolts. To boost the current produced, arrays of the flexible charge pumps could be constructed and connected in series. Multiple layers of the generators could also be stacked to form modules that could be implanted in the human body to power blood pressure sensors or other devices.
When the modules are mechanically stretched and released, the zinc oxide material generates a piezoelectric potential that alternately builds up and then is released. The wires are encapsulated in a flexible plastic substrate with two bonded ends; a Schottky barrier controls the alternating flow of electrons, and the piezoelectric potential is the driving force of the charge pump.
To measure generated electric energy in tests, researchers subjected the substrate and attached zinc oxide wires to periodic mechanical bending created by a motor-driven mechanical arm. Bending induces tensile strain, which creates a piezoelectric potential field along the laterally packaged wires. That in turn drives a flow of electrons into an external circuit, creating the alternating charge and discharge cycle – and corresponding current flow. Wang envisions a family of small-scale generators enabling development of a new class of self-powered wireless sensing systems that could gather, store, and transmit information without an external power source.
Related News

FPL stages massive response to Irma but power may not be back for days or weeks
MIAMI - Teams of Florida Power & Light linemen, assisted by thousands of out-of-state utility workers, scrambled across Florida Monday to tackle the Herculean task of turning the lights back on in the Sunshine State.
The job is quite simply mind-boggling as Irma caused extensive damages to the power grid and the outages have broken previous records.
By 3 p.m. Monday, some 3.47 million of the company's 4.9 million customers in Florida were without power. This breaks the record of 3.24 million knocked off the grid during Hurricane Wilma in 2005, according to FPL spokesman Bill Orlove.
Prepared to face massive outages, FPL brought some 18,000 utility…