The phrase "are a power source" is correct and usable in written English.
It can be used when describing something that provides energy or power, such as a device, system, or entity.
Example: "Batteries and generators are a power source for many electronic devices."
Alternatives: "serve as a power source" or "function as a power source".
Mr. Iconis's keyboard and occasional vocals are a power source pumping energy into the cast, which includes Nick Blaemire, Katrina Rose Dideriksen, Badia Farha, Sarah Glendening, Eric William Morris, Lance Rubin and Jason SweetTooth Williams.
He said they are: a power source, such as an AA battery or a fuse; an initiator, like the fuse itself or a cellphone or a timing device; an explosive; and a switch.
Generally, different ratios of biodiesel are blended with fossil fuel for use in diesel engines, which are recognized for energy generation and are a power source providing higher efficiency and ruggedness in the field of transportation.
By integrating with the multi-unit HEG, the household faucet can be a power source to supply clean energy continuously.
Another minus: You can't use the Tenori-On with batteries anymore so there needs to be a power source anywhere you use it.
This output might suit many applications, such as being a power source for home or office electronics, says co-developer and nanoscientist Zhong Wang of the Georgia Institute of Technology in Atlanta.
Unfortunately, there are a number of obstacles between this concept and reality, least of which being a power source that can fit into such a thin device and still give our digital obsessions enough juice for a full day.
It's a power source that American has in spades.
After that, he said, coal will no longer be a power source for the city.
It may not be renewable energy, but it still may be a power source for our future.
DO NOT play on your mobile device as it is charging unless your charger is a power source.
