A beater; a striker.

A unit on the EDM machine which periodically causes the electrode to retract for a short period of time to aid in flushing a deep or blind cavity. Also commonly called a RAM cycler or jump control.

A device used in early electrical- resistivity well logging instrumentation to pulsate (or alternate) the survey current and measured signals.

A device that varies the vacuum (pressure) between the liner and shell, thus opening and closing the liner to provide milk and massage to the teat.

That which beats or throbs in working.