A method of assembling an eddy current probe for use in nondestructive testing of a sample is described. In an image reading apparatus having a plurality of reading definition values, the state of a reading subject is monitored with first definition. A large number of fixed parameters can be programmed by forming an interconnect matrix connecting the programming pins to the input terminals corresponding to the fixed parameters. The protection circuit is configured to control a turn-on condition of the protection circuit. In order to construct the auxiliaries in an easily mountable manner and to advantageously accommodate them on the housing structure of the internal-combustion engine, the generator and the water pump form a constructional unit which is connected with the housing structure of the internal-combustion engine. The plasma generation apparatus includes two oppositely arranged plasma guns each injecting a discharge gas to be ionized, and having a cathode for emitting electrons, and a converging coil for forming a magnetic flux to guide the emitted electrons, and polarities of the converging coils with respect to the cathodes in the two plasma guns are opposite to each other.