Smoke testing refers to various classes of tests of systems, usually intended to determine whether they are ready for more robust testing. The expression probably was first used in

plumbing Plumbing is any system that conveys fluids for a wide range of applications. Plumbing uses pipes, valves, plumbing fixtures, tanks, and other apparatuses to convey fluids. Heating and cooling (HVAC), waste removal, and potable water deliver ...

in referring to tests for the detection of cracks, leaks or breaks in closed systems of pipes.Stevenson, Thomas.
A Treatise on Hygiene and Public Health, Volume 1
'. J. & A. Churchill. 1892, p. 776. By metaphorical extension the term is used in

electronics The field of electronics is a branch of physics and electrical engineering that deals with the emission, behaviour and effects of electrons using electronic devices. Electronics uses active devices to control electron flow by amplification ...

. In ''Lessons Learned in Software Testing'', Cem Kaner, James Bach, and Brett Pettichord provided the origin of the term: "The phrase ''smoke test'' comes from

electronic Electronic may refer to: *Electronics, the science of how to control electric energy in semiconductor * ''Electronics'' (magazine), a defunct American trade journal *Electronic storage, the storage of data using an electronic device *Electronic co ...

hardware testing. You plug in a new board and turn on the power. If you see smoke coming from the board, turn off the power. You don't have to do any more testing."Kaner, Bach, and Pettichord. ''Lessons Learned in Software Testing''. Wiley Computer Publishing, 2002, p. 95.

In electronics and electrical engineering

and electrical engineering, the term smoke test or power on test is used to refer to the first time a circuit under development is attached to power, which will sometimes produce actual smoke if a design or wiring mistake has been made. Most often, this smoke comes from burning

resistor A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias activ ...

s, which produce a unique smell. For certain circuits, overheating and burning due to circuitry that is still not properly operating can be avoided by slowly turning up the input voltage to the unit under test by using a variable

autotransformer An autotransformer is an electrical transformer with only one winding. The " auto" (Greek for "self") prefix refers to the single coil acting alone, not to any kind of automatic mechanism. In an autotransformer, portions of the same winding act ...

and watching the

electric current An electric current is a stream of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is measured as the net rate of flow of electric charge through a surface or into a control volume. The movin ...

consumption. Overloaded integrated circuits typically produce "blue smoke" (or

magic smoke Magic smoke (also factory smoke, blue smoke, or the genie) is a humorous name for the caustic smoke produced by severe electrical over-stress of electronic circuits or components, causing overheating and an accompanying release of smoke. The s ...

). "Blue smoke" is the subject of jokes among technicians who refer to it as if it were a

genie Jinn ( ar, , ') – also romanized as djinn or anglicized as genies (with the broader meaning of spirit or demon, depending on sources) – are invisible creatures in early pre-Islamic Arabian religious systems and later in Islamic m ...

in the circuit: ''It's the blue smoke that makes it work—let out the blue smoke and it won't do anything.''

References

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