gResistor

gResistor is a desktop calculator for resistor colour codes. The user selects the sequence of coloured bands printed on a component, and the program reports the resistance value and tolerance that the code stands for, replacing a printed chart or a memorised mnemonic. The scope is narrow by design: it identifies passive components and does nothing further, with no schematic editing, circuit simulation or parts inventory attached.

That narrowness is what makes it useful as a small addition to a bench setup or an electronics course, where the same lookup is repeated many times in a session and the printing on a physical resistor can be faded or ambiguous. Anyone who reads the bands unaided will have little need for it.

The program is written by Stefano Prina and released under LGPL-3.0-or-later, so the code may be reused by other projects on the terms that licence sets out. The entry here refers to the Linux packaging; no build for other operating systems is listed.