user defined units

Forum|Forum|7 months ago
August 23, 2025
1 reply
537 views

Hello, I defined an electron volt in terms of Joules, and tried to convert Joules to electron volts in prime 11, and got an error saying electron volt was undefined. What am I doing wrong?

I get the same error when I replace the J with the eV in the 2nd to last expression. This worked in MathCAD 15.

Thanks for the help, Paul

Physics

Best answer by StuartBruff

When you define eV you need to set the Math Label to 'Unit', not use the default 'Variable'.

2025 08 23 F.png

The Math Label can be found in the middle of the Math Ribbon.

Stuart

S

StuartBruff

Answer

23-Emerald V

When you define eV you need to set the Math Label to 'Unit', not use the default 'Variable'.

2025 08 23 F.png

The Math Label can be found in the middle of the Math Ribbon.

Stuart

P

ptc-1385443

Author

4-Participant

Thanks, Stuart, that worked.

Sent from my iphone

S

StuartBruff

23-Emerald V

No worries.

I'm not sure whether eV (or other user-defined unit) should be auto-converted to Unit at its first use in the unit placeholder or not.

Stuart

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