Category: Bridges

Detectors Types

Detectors Types: The Detectors Types are as follows For low frequency, the most convenient detector is the vibration For ordinary laboratory work at frequencies up to a few 100 Hz, the moving coil type of instrument is usually employed. It has a high In high voltage testing, the moving magnet type of vibration galvanometer with remote […]

Wagner Earth Connection

Wagner Earth Connection: Wagner Earth Connection – When performing measurements at high frequency, stray capacitances between the various bridge elements and ground, and between the bridge arms themselves, become significant. This introduces an error in the measurement, when small values of capacitance and large values of inductance are measured. An effective method of controlling these capacitances, […]

Wien Bridge Circuit Diagram

Wien Bridge Circuit Diagram: The Wien Bridge Circuit Diagram shown in Fig. 11.27 has a series RC combination in one arm and a parallel combination in the adjoining arm. Wien’s bridge in its basic form, is designed to measure frequency. It can also be used for the measurement of an unknown capaci­tor with great accuracy. […]

Scherings Bridge Experiment

Scherings Bridge Experiment: A very important bridge used for the precision measurement of capacitors and their insulating properties is the Scherings Bridge Experiment. Its basic circuit arrangement is given in Fig. 11.25. The standard capacitor C3 is a high quality mica capacitor (low-loss) for general measurements, or an air capacitor (having a very stable value and […]

Hays Bridge Circuit

Hays Bridge Circuit: Hays Bridge Circuit, shown in Fig. 11.23, differs from Maxwell’s bridge by having a resistance R1 in series with a standard capacitor C1 instead of a parallel. For large phase angles, R1 needs to be low; therefore, this bridge is more convenient for measuring high-Q coils. For Q = 10, the error is […]

Maxwell Bridge Theory

Maxwell Bridge Theory: Maxwell Bridge Theory, shown in Fig. 11.21, measures an unknown inductance in terms of a known capacitor. The use of standard arm offers the advantage of compactness and easy shielding. The capacitor is almost a loss-less component. One arm has a resistance R1 in parallel with C1, and hence it is easier […]

Comparison Bridge

Comparison Bridge: There are two types of Comparison Bridge, Namely 1.Capacitance Comparison Bridge 2.Inductance Comparison Bridge 1.Capacitance Comparison Bridge Figure 11.18 shows the circuit of a capacitance comparison bridge. The ratio arms R1, R2 are resistive. The known standard capacitor C3 is in series with R3. R3 may also include an added variable resistance needed to balance the […]

Digital Readout Bridge

Digital Readout Bridge: The tremendous increase in the use of digital circuitry has had a marked effect on electronic test instruments. The early use of digital circuits in bridges was to provide a Digital Readout Bridge. The actual measuring circuitry of the bridge remained the same, but operator error in observing the reading was eliminated. […]

Bridge Controlled Circuit

Bridge Controlled Circuit: Bridge Controlled Circuit – Whenever a bridge is unbalanced, a potential difference exists at its output terminal. The potential difference causes current to flow through the detector (say, a galvanometer) when the bridge is used as part of a measuring instrument. When the bridge is used as an error detector in a […]

Kelvins Bridge theory

Kelvins Bridge theory: When the resistance to be measured is of the order of magnitude of bridge contact and lead resistance, a modified form of Wheatstone’s bridge, the Kelvins Bridge theory is employed. Kelvins Bridge theory is a modification of Wheatstone’s bridge and is used to measure values of resistance below 1 Ω. In low resistance […]