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What are the conditions to be satisfied to make an AC bridge balanced?
Two balance equations are always obtained for an ac bridge circuit. This follows from the fact that for balance in an ac bridge, both magnitude and phase relationships must be satisfied. This requires that real and imaginary terms must be separated, which give two equations to be satisfied for balance.
What are the two conditions of balance in AC bridge?
Detailed Solution. Concept: In AC bridges, there are two conditions to get bridge balance condition. These two are independent conditions for balance and both of them must be satisfied for the bridge to be balanced.
What are the advantages of AC bridges?
A.C. bridges form the most convenient method of measuring effective resistance, self-inductance, mutual inductance, capacitance, and other associated quantities (such as the Q-factor of coils and loss angles of capacitors) at frequencies up to the lower radio-frequency range.
Why Wagner ground connection is used in AC bridges?
The Wagner earthing device is used for removing the earth capacitance from the bridges. It is a type of voltage divider circuit used to reduces the error which occurs because of stray capacitance. The Wagner Earth device provides high accuracy to the bridge.
What is the principle of operation of an AC bridge?
AC bridge circuits work on the same basic principle as DC bridge circuits: that a balanced ratio of impedances (rather than resistances) will result in a “balanced” condition as indicated by the null-detector device.
Which bridge is used in case of AC signal conditioning?
Wien frequency bridge
The Wien frequency bridge is arranged such that the bridge balances to provide a zero output at only one frequency of the applied a.c. This means that the Wien Bridge can be used as a notch filter to block a particular frequency for a possible signal conditioning requirement.
How are balance equations used in AC bridges?
AC bridge circuits are used in phase shifting and for the filtration of undesirable signals. It is also used to measure the frequency of audio signals. For AC bridge circuits, two balance equations are always obtained. One is the magnitude and the other is phase equation.
What is a balance or null condition in an AC bridge?
The detector current I d should be zero. The potential difference between the detector node should be zero. Now, the question arises what is a balance or null condition in an AC bridge? It is a condition when certain specific applied circuit situation causes the detector current to become 0.
What do you need to know about AC bridges?
So, here impedance parameters will get multiplied and angles will be added. This condition is known as phase criteria. So, in a bridge balance condition, magnitude and phase criteria should be satisfied simultaneously. AC bridges are used to find unknown impedances along with associated parameters.
What are the arms of an AC bridge?
The bridges have four arms, two have non-inductive resistance and the other two have inductances with negligible resistance. The l 1 and R 1 are the unknown quantities which are measured in terms of R 2, R3, R 4 and L 2 .