Vibrating-Wire Transducer

a transducer that converts pressure, displacement, flow rate, stress, or other quantities into electrical signals (current, voltage, or frequency).

Table 1b. Sponsors of some Soviet and foreign scientific research vessels
Vessel	Sponsor	Vessel	Sponsor
Vitiaz’ ...............	Academy of Sciences, USSR	Akademik Topchiev ...............	Academy of Sciences, USSR
Mikhail Lomonosov ...............	Academy of Sciences, Ukrainian SSR	Akademik Vavilov ...............	Academy of Sciences, USSR
		Merkurii ...............	GUGMS
Iu. M. Shokal’skii ...............	GUGMS	Vema ...............	USA
A. L. Voeikov ...............	GUGMS	Atlantis II ...............	USA
PetrLebedev ...............	Ministry of the Shipbuilding Industry	Oceanographer ...............	USA
		Melville ...............	USA
Ob’ ...............	Ministry of the Merchant Marine	Hero ...............	USA
		Glomar Challenger ...............	USA
Akademik Kurchatov ...............	Academy of Sciences, USSR	Calypso ...............	France
Passat ...............	GUGMS	Jean Charcot ...............	France
Kallisto ...............	Academy of Sciences, USSR	Meteor ...............	Federal Republic of Germany
Zaria ...............	Academy of Sciences, USSR	Discovery ...............	Great Britain
Akademik Knipovich ...............	Ministry of Fisheries	Sars Michael ...............	Norway
Evrika ...............	Ministry of Fisheries	Hakuho Maru ...............	Japan
Odissei ...............	Ministry of Fisheries	UmitakaMaru ...............	Japan
Akademik Arkhangel’skii ...............	Ministry of Geology	General San Martin ...............	Argentina
Poisk ...............	Ministry of Geology	Kosmonavt lurii Gagarin ...............	USSR
Professor Bogorov ...............	Academy of Sciences, USSR	Akademik Sergei Korolev ...............	USSR
Akademik A. Kovalevskii ...............	Academy of Sciences, Ukrainian SSR	Kosmonavt Vladimir
		Komarov ...............	USSR
Professor Dobrynin ...............	Academy of Sciences, USSR	General Vandenberg ...............	USA
Morskoi geofizik ...............	Academy of Sciences, USSR	Redstone ...............	USA
Valerian Uryvaev’ ...............	GUGMS ...............	American Mariner	USA
G. Iu. Vereshchagin ...............	Academy of Sciences, USSR

The sensing element in a vibrating-wire transducer consists of one or more taut tungsten or steel wires. The operation of the transducer is based on the dependence of the wire’s natural vibration frequency f₀ on the wire’s length I, mass m, and tension F (or mechanical stress σ or elongation ∆l):

where ρ and E are the density and elastic modulus, respectively, of the wire material. The principal components of a vibrating-wire transducer are (1) the mechanical system containing the wire or wires and (2) an auxiliary transducer, usually of an electromagnetic or permanent-magnet type, that converts changes in the vibration frequency of the mechanical system into changes in electric-circuit parameters.

Figure 1. Schematics of vibrating-wire transducers: (a) single-wire, (b) differential; (1)wire, (2) housing, (3) output transducer, (4) diaphragm, (5) spring, (6) output signal, (U) supply voltage for output transducer, (e) electromotive force at transducer output, (p) and (F) measured parameters (pressure and force)

A distinction is made between vibrating-wire transducers with one wire and those with two identical wires (Figure 1). In the second type, which may be called a differential vibrating-wire transducer, the ambient temperature and pressure have much less effect on the results of the conversion of the input parameter. The principal shortcoming of the single-wire transducers is the extreme nonlinearity of the static characteristics. The static characteristics of differential transducers are considerably more linear.

The accuracy of conversion of the input quantity by the transducer is increased when the stiffness of the wire is the principal component in the stiffness of the mechanical system. An example of a vibrating-wire transducer is the differential vibrating-string gravimeter, the relative error of whose output does not exceed ±(10^–6–10^–8).

A. V. KOCHEROV