| 摘要 |
<p>Disclosed is an electrodynamic ultrasonic transformer having at least one exciting coil and one receiving coil for nondestructive material testing by means of ultrasonics. In order to reduce the dead times and to remove or, respectively, keep as little as possible negative influences occurring during the measuring of different test piece material and at distance variations without adversely affecting the signal/ noise ratio, it is proposed that those parts of the exciting coil and/or receiving coil designed for current conducting be made of resistance material which is suitable for structural elements embodying electric resistors, and which material will not essentially obstruct the current flow during the exciting phase of the current, and after termination of the excitation will rapidly reduce the energy stored in stray and coupling fields.</p> |
