Symbol 5146 from IEC 60417 - Title/Meaning: Adjustment to a minimum Function/description: To identify the control by means of which a quantity is adjusted to its minimum value.
Additional information: 
For example: ""zero"" control or balancing of a bridge device; rejection of an unwanted signal; minimum deviation of a meter, indicator, etc
Published in: First edition, 1973
Own work using: iso.org/obp/graphics/grs/0e57972e-bd69-4682-967e-2773aa5ddefe 200.png
Vectorization:  Mrmw