Explore your understanding of AC bridges with this quiz covering Hay, Wien, and Schering Bridge principles, applications, and balancing techniques. Perfect for engineering students and professionals seeking to assess their grasp of impedance measurement circuits and their practical uses in electrical engineering.
In a Hay bridge designed to measure an inductance with a high Q-factor, which component is placed in series with the unknown inductor?
Explanation: A non-inductive resistor is connected in series with the unknown inductor in a Hay bridge to minimize errors from mutual inductance and maintain measurement accuracy. A standard capacitor is used elsewhere in the bridge and is not in series with the inductor. Variable and fixed resistors in parallel alter the bridge’s configuration and are not the standard series arrangement for Hay bridges. This setup is essential to accurately measure high-Q inductors.
Which practical measurement is most commonly performed using a Wien bridge setup in laboratories?
Explanation: The Wien bridge is primarily used for accurate measurement of an unknown signal’s frequency, utilizing its frequency-selective properties. While it can be used for other types of measurements, its chief application is not low resistance, high capacitance, or transformer ratios. Other specialized bridges are better suited for those purposes. This makes the Wien bridge particularly valuable in audio and signal processing domains.
A Schering bridge is especially suitable for the measurement of which electrical parameter in insulating materials?
Explanation: The Schering bridge is designed to measure capacitance and dielectric loss, making it ideal for assessing the quality of insulating materials. Inductance and resistance are measured using different bridge configurations. Voltage regulation is not a direct function of any bridge circuit. That is why the Schering bridge is heavily used in dielectric testing and insulation analysis.
When a Hay bridge is balanced, the phase angle between the voltage across the bridge and the current through the unknown inductor is typically:
Explanation: At balance, the phase angle in a Hay bridge is about 90 degrees because of the inductive (L) elements dominating the bridge. A phase angle of 0 degrees corresponds to purely resistive circuits, which does not apply here. Forty-five degrees is not characteristic in this balanced situation, and the angle is not variable or unpredictable due to the precise bridge configuration. This property is essential for accurate high-Q inductance measurement.
For a Wien bridge to achieve balance, which mathematical relationship must exist between its resistance (R) and capacitance (C) arms given an applied frequency f?
Explanation: The correct balance condition for a Wien bridge is R1 multiplied by C1 equals R2 multiplied by C2, which ensures the frequency-selective property of the bridge. Adding resistances and capacitances does not provide the correct balance relationship. Dividing R by C or including frequency in a multiplicative manner does not lead to accurate balancing. This formula is crucial for extracting frequency information from the bridge setup.