[en] There is a high demand for the development of small, reliable, cheap, up-to-date cyclotrons of variable energy all over the world. The main properties (the energy and the current of the beams, data on the magnetic and RF system) of the commercially available, compact cyclotrons are concisely described. MGC cyclotron made in the Sowjetunion is deatiled. The use of cyclotrons in nuclear physical research is outlined. In most cases (p, n), (d, n), (³He, n), (⁴He, n) and (α, n) reactions can be accomplished at maximum cross section, isotopes of neutron feilure or neutron surplus can be made. Numerous isotopes can be produced by cyclotrons which do not form in reactors. The following isotopes can be well used for medical, biological and other purposes: ⁴³K, ⁸¹Rb/sup(81m)Kr, ⁵²Fe, ¹¹C, ¹³N, ¹⁵O. (V.N.)