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.
1 Northwest Garden News provides an overview of the installation process. 2  This Old House explains how to lay a gravel path, estimating that the project takes 2-4 hours; is of easy to moderate difficulty; and costs about $300 -$400 for a 100'-long and 2.5'-3'-wide path. To estimate the cubic yards required for a specific project, multiply length by width by depth and then divide by 27. 2  For example, to lay a 3 bed of gravel on a path 3' wide and 100' long, convert the 3 to 0.25'; multiply 0.25 x 3 x 100 and divide by 27, which equals 2.78 cubic yards.