The Wehnelt Current Interrupter

Article metrics


THE form of contact breaker recently introduced by Wehnelt is attracting so much notice, that it may be worth while to draw attention to an essentially identical arrangement described by Spottiswoode for use with an induction coil, more than twenty years ago (Proc. Roy. Soc., vol. xxv. p. 549). He says: “Another form of contact breaker was also occasionally used. The principle upon which it was based was the sudden disruption of a thin film of conducting liquid by a discharge between the electrodes of a circuit. The mode of effecting this was to make one electrode terminate in a platinum plate fixed in a horizontal position, and supplied with a uniform film of dilute sulphuric acid; the other in a platinum point, the distance of which from the plate is capable of delicate adjustment by means of a screw. Electro-motive force required for this break is not less than that of five cells of Grove. As soon as the current passes, the fluid between the plate and point will be decomposed, and electrical continuity broken. This done, the fluid flows back again, and continuity is restored. By a proper adjustment of the supply of fluid and of the distance between the electrodes (the latter varying from ˙05 to ˙001 of an inch), the number of disruptions may be made to attain 1000 per second. The currents delivered by this form of break are exceedingly uniform, and the effects produced are quite equal in delicacy to those produced by the electro-magnetic or by the wheel break.”

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

STRUTT, R. The Wehnelt Current Interrupter. Nature 59, 510 (1899) doi:10.1038/059510a0

Download citation


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.