speedometer


Also found in: Dictionary, Thesaurus, Medical, Legal, Financial, Wikipedia.
Related to speedometer: Speed test

speedometer,

instrument that indicates speed. A cable from an automotive speedometer is attached to the rear of the transmission of an automobile; the cable turns at a rate proportional to the speed of the car. In a very common type of speedometer the other end of the cable is attached to a simple magnetic device inside the speedometer. In response to the rotating cable, this device moves a needle along a calibrated dial to indicate the speed of the automobile. Another type of automobile speedometer uses centrifugal force and operates in a manner similar to a flyball governorgovernor,
automatic device used to regulate and control such variables as speed or pressure in the functioning of an engine or other machine. A governor may be an electric, hydraulic, or mechanical device, or it may employ some combination of electric, hydraulic, and mechanical
..... Click the link for more information.
. The airplane speedometer is called an air-speed indicator. A dial that registers the speed in kilometers or miles per hour is actuated by the wind pressure in a tube located where it is not affected by the air stream from the engine. The speed of a watercraft is frequently determined by means of a patent or taffrail log. In this device a small propeller, which is towed astern, revolves as it moves through the water, activating a calibrated dial aboard the vessel. In another type of marine speedometer a tiny fin projects from the hull below the waterline. The resistance of the water to the passage of the fin is converted on a dial into terms of speed in knots.

Speedometer

 

an instrument used in motor vehicles to measure the speed of travel and the distance traveled. The speed indicator of a speedometer is magnetically operated, and the distance counter (odometer) operates mechanically by means of rollers. In mechanically driven speedometers, both the speed indicator and the odometer are connected by means of a flexible cable to a set of reduction gears, one gear of which is driven from the driven shaft of the vehicle’s transmission. In electrically driven speedometers, the transmission’s driven shaft is connected to a contact breaker that functions as a pickup and converts direct current into three-phase alternating current. The frequency of the alternating current is proportional to the speed of rotation of the driven shaft. The current feeds an electric motor, whose rotor rotates at the same speed as that of the pickup.

REFERENCES

Galkin, Iu. M. Elektrooborudovanie avtomobilei i traktorov, 2nd ed. Moscow, 1967.

speedometer

[spi′däm·əd·ər]
(engineering)
An instrument that indicates the speed of travel of a vehicle in miles per hour, kilometers per hour, or knots.

speedometer

a device fitted to a vehicle to measure and display the speed of travel

speedometer

A pattern of lights displayed on a linear set of LEDs (today) or nixie tubes (yesterday, on ancient mainframes). The pattern is shifted left every N times the operating system goes through its main loop. A swiftly moving pattern indicates that the system is mostly idle; the speedometer slows down as the system becomes overloaded. The speedometer on Sun Microsystems hardware bounces back and forth like the eyes on one of the Cylons from the wretched "Battlestar Galactica" TV series.

Historical note: One computer, the GE 600 (later Honeywell 6000) actually had an *analog* speedometer on the front panel, calibrated in instructions executed per second.
References in periodicals archive ?
CAR CRAZY: Pictures taken from You Tube clearly show the speedometer reading at more than 130mph as the teenage passengers film themselves making victory signs and laughing at their illegal antics
It returned to Saga shortly after takeoff, after the pilot and copilot discovered the readings on their speedometers differed.
Similarly, the LCD screen that serves as speedometer, fuel gauge, trip-meter and odometer is secreted into a deeply recessed chrome insert on top of the fuel tank.
Isspro said that the mechanical pressure and temperature gauges, as well as the pitot speedometer, feature a phosphor bronze bourdon tube linked to a gear and pinion arrangement for accurate indication.
Upsizing your truck's wheel and fire package for hunting season, or swapping in a new gear ratio, effectively changes your speedometer reading.
"Our technique allows us to read the preserved growth-rate record, much like reading the speedometer in a car."
There was no engine, no speedometer or altitude meter.
At trial, Graham said he hooked up a cruise-control mechanism and a speedometer to a plywood board, and his expert witness turned on an electric household drill near the mechanism's electronic sensor.
* Nonfatal traffic accidents involving speedometer and/or headlight examinations, except cases involving law enforcement officers or State and local government officials
A new use of an old device, a speedometer, will help farmers more accurately apply the correct amounts of fertilizer and herbicides.