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Pentode symbol dh pl.svg anoda katoda siatki arzenie Pentodesymbolpl svg UTC Pentodesymbolpl svg PentodeSymbolde svg erstellt von de User RokerHRO geaendert von de User Fgli derivative work RJB talktalk Directly heated version RJB Pentodesymbolpl svg PDuserw Original upload log This image is derivative work of the following