variometer


Also found in: Dictionary, Thesaurus, Wikipedia.

variometer

[‚ver·ē′äm·əd·ər]
(electromagnetism)
A variable inductance having two coils in series, one mounted inside the other, with provisions for rotating the inner coil in order to vary the total inductance of the unit over a wide range.
(engineering)
A geomagnetic device for detecting and indicating changes in one of the components of the terrestrial magnetic field vector, usually magnetic declination, the horizontal intensity component, or the vertical intensity component.

Variometer

 

in radio engineering, a variable-inductance coil designed for tuning oscillatory circuits. The type of variometer used in the 1920’s and 1930’s was divided into two sections connected in series: a fixed outer coil (the stator) and a movable inner coil (the rotor). The inductance of the variometer is equal to the sum of the inductances of the sections and the mutual inductance between them, which changes significantly when the rotor is turned 180°. This type of variometer was widely used to retune the frequency of the oscillatory circuit of a radio receiver. The variometer subsequently lost its original form and use and is now used in radio receivers as an inductance coil containing within its winding a core made of a magnetic dielectric that changes the induction within insignificant limits in order to adjust the frequency of the oscillatory circuit.

variometer

variometerclick for a larger image
Two types of variometer.
An instrument that is a sensitive rate of climb and descent indicator. Used in sailplanes and gliders, it indicates climb and descent almost instantaneously, unlike conventional vertical speed indicators, which suffer from lag.
References in periodicals archive ?
The simplicity and low cost of the basic variometer are advantages but the lack of automatic recording of the output is its disadvantage.
In contrast to the variometer, the fluxgate is a much more complex, and recent (developed in the 1930s), sensor.
For this paper, a fluxgate sensor and a home-made variometer were installed in the author's study.
To log the outputs from the sensors a home-made data acquisition system was constructed which could count the pulses from the fluxgate and digitise the analogue signal from the variometer.
The variometer was constructed in a cylindrical plastic food storage jar, 12cm in diameter and 18cm high.
In both fluxgate and variometer sensors, a temperature sensor was co-located with the sensor.
Figures 6 and 7 show variometer and fluxgate observations taken on 2011 April 6 & 7.
The Hall-effect sensors in the variometer, by comparison, are easier to use and show no detectable variation with temperature.
Note that while the fluxgate sensors should vary (almost) linearly with the magnitude of disturbances in the magnetic field, the voltages from the variometer will not have so simple a relationship (but, for detecting auroral conditions, this is not a problem).
If a computer-less design is wanted the variometer output can be fed to a voltmeter using a simple analogue circuit such as that shown in Figure 11.