Symbol 6012 from IEC 60417 - Title/Meaning: Constant voltage isolating transformer, general Function/description: To identify an isolating transformer intended to limit the influence of the input voltage variations.
Additional information: 
To indicate a fail-safe function, the letter F may be used adjacent of the graphical symbol.
To identify the isolating transformer of the type of constant voltage non-short-circuit proof, the symbol element 5221 shall be replaced by symbol 5944.
To identify the isolating transformer if the type of constant voltage short-circuit proof, the symbol element 5221 shall be replaced by symbol 5945
Editorial error in Note (2) was corrected by IEC 60417-C00079.
Own work using: iso.org/obp/graphics/grs/835dcfe6-ed0d-4405-a59b-42c9fda727fc 200.png
Vectorization:  Mrmw