  The Euler number is a new topological number recently debuted in the
topological physics. Unlike the Chern number defined for a band, it is defined
for interbands. We propose a simple model realizing the topological Euler
insulator for the first time. We utilize the fact that the Euler number in a
three-band model in two dimensions is reduced to the Pontryagin number. A
skyrmion structure appears in momentum phase, yielding a nontrivial Euler
number. Topological edge states emerge when the Euler number is nonzero. We
discuss how to realize this model in electric circuits. We show that
topological edge states are well signaled by impedance resonances.
