★ A lot of crystalline cuts of langasite plates are investigated. ★ DC electric field influence tends to the decreasing of crystalline symmetry. ★ A quantitative coefficient M characterize the degree of wave hybridization. ★ Extreme values of the controlling coefficients of phase velocities are determined.
Paper is presented the results of computer simulation. Effect of the homogeneous dc electric field influence on the propagation of zero and first order Lamb and SH waves in piezoelectric langasite single crystal plates for a lot of cuts and directions have been calculated. Crystalline directions and cuts with maximal and minimal influence of dc electric field have indicated. Effect of hybridization of plate modes has been discussed.