Simple, portable and low-cost experiments as RC and RL series circuits are
proposed as examples to experiment with DC circuits. Very common elements are
used: few electronics components (resistors, capacitors, coils and connecting
wires) and two martphones. We consider the charging and discharging of a
capacitor in the RC circuit and also that of coil in the RL circuit. Using a
smartphone as a oscilloscope we observe voltages variations which are the
transient response to a square signal generated in the second smartphones.
These voltage variations are directly related to the electrostatic or magnetic
energy stored in the circuits. The experimental data have been collected with
the smartphone used as an oscilloscope. This approach which avoids the use of
expensive signal generators, oscilloscopes, or any specialized hardware can be
performed in less-favored contexts and even as a home assignment.Comment: 7 pages, 7 fig