Shorting a node pair changes the circuit determinant, whereas nulling a voltage or a branch current does not. A better expression for disabling a source would be 'nullifying' or 'setting to zero'.

Middlebrook answers this questing in his 1EET paper.


  1. R D Middlebrook. Null double injection and the extra element theorem. IEEE Transactions on Education 32(3):167–180, 1989. URL, DOI