| 摘要 |
<p>PURPOSE: To protect a resonator by protecting it from high voltage in a marker having an antenna coil functioning as a coil for electrofusion when a pipe is welded. CONSTITUTION: A marker is provided on electrofusion pipe in which a coil 5 for electrofusion is buried in a coupling part, in which the coupling part is melted by heat generated by the coil 5 by energizing the coil 5 and in which the pipe is welded. In the marker, a resonator 7 which is connected in parallel with the coil 5 and which uses the coil 5 as an antenna coil and a resonator protective element 9 which is connected in parallel with the resonator 7 and which limits a voltage to be applied to the resonator 7 are installed.</p> |
