You will need
- tester, table of specific resistances.
To reduce the force of the current on the circuit and adjust the values on which it depends. To determine these values, use the equation, which is one of the types of writing Ohm's law I = U•S /(ρ• l). Collect the chain, adding to the test section of the rheostat. Connect it to the source current. After that, changing the settings of the rheostat, reduce tension in the area. To get the voltages, connect the parallel section of the tester and make a measurement. Then, by connecting the tester to the site consistently and changing the settings, measure the strength of current in the circuit. Reduce the voltage on the circuit n times. By measuring the strength of the current, make sure that it also decreased n times.
Change the resistance of the chain. To do this, define the resistivity of the material conductors by a special table. To reduce the power current conductors pick up the same size, but with high resistivity. How many times will increase the resistivity, as many times decreases the strength of the current.
If you can not find the other guides, change their geometric dimensions. Reduce the cross-sectional area of the conductor. For example, if the wire is stranded, get a few lived. How many times will decrease the cross-sectional area, at the same time decreases the current. The second method is to increase the overall length of the conductors. How many times will increase the length of conductors on the circuit, as many times decreases the strength of the current.
Another easy way is to attach a chain to the source of current with a lower electromotive force. How many times will decrease the value of the EMF, so many times will decrease the power current. These techniques can be combined to achieve the best effect. For example, lowering the voltage by 2 times, increasing the length of the conductors 3 times and reducing the cross-sectional area 4 times, you will receive a dimming current in 2•3•4=24 times.