A discrete total variation calculus with variable time steps is presented for mechanico-electrical systems where there exist non-potential and dissipative forces.By using this discrete variation calculus,the symplectic-energy-first integrators for mechanico-electrical systems are derived.To do this,the time step adaptation is employed.The discrete variational principle and the Euler-Lagrange equation are derived for the systems.By using this discrete algorithm it is shown that mechanico-electrical systems are not symplectic and their energies are not conserved unless they are Lagrange mechanico-electrical systems.A practical example is presented to illustrate these results.