1 An electric current is the overall movement of charged particles in one direction. 2  To obtain an electric current, there needs to be a continuous circuit from one terminal of a battery to the other. 3  An electric current in a circuit transfers energy from the battery to the circuit components.
A pea gravel walkway or patio costs about $5 per square foot, installed, including a layer of base rock. If you'd like to install it yourself, it will cost half as much.Add in the cost of a header or Bender Board. A wood header is about $5 per linear foot; a metal header is $6 (black metal disappears well).You won't need a header if you're installing gravel against a house, fence, or raised bed.dd in the cost of a header or Bender Board. A wood header is about $5 per linear foot; a metal header is $6 (black metal disappears well). You won't need a header if you're installing gravel against a house, fence, or raised bed.
Cost. To get the cost of gravel, multiply the number of cubic feet you need by the cost per cubic foot. In the example, we need 150 cubic feet; if it costs $10 per cubic foot, then the gravel costs $1,500.