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.
He says the average sized driveway is about 20-by-20 feet, which requires about 13 tons of crushed rock and costs $1,300 to $1,500, including materials and labor. Schott estimates the average cost for him to install a gravel driveway is $1,200 to $1,500. According to CostHelper, the prices range drastically, from as low as $300 to thousands of dollars. A 12-by-25-foot driveway, with at least 4 inches of gravel, can cost about $300 to $1,000. Professionals recommend having anywhere from 4 to 8 inches of gravel.