What is Carey Foster bridge experiment?
In electronics, the Carey Foster bridge is a bridge circuit used to measure medium resistances, or to measure small differences between two large resistances. It was invented by Carey Foster as a variant on the Wheatstone bridge.
Why is Carey Foster bridge so sensitive?
The Carey Foster bridge is so sensitive because it is used for measuring the smallest decimal change in the resistance. The sensitivity of Carey Foster bridge is proportional to the length of the wire used in the bridge.
What are advantages of Carey Foster bridge?
Advantages. It gives an accurate measurement of the difference in the resistance. Whenever the Carey Foster bridge is used for measurement, it gives precise results as compared to other equipment. Only one unknown resistance is sufficient to measure the difference.
Why should p and q be equal in Carey Foster bridge?
Let P, Q, R and S are the four resistors used in the bridge. The resistances of P and R are known while the R and S are the unknown resistors. The slide wire of length L is placed between the resistance R and S. The resistor P and Q are adjusted so that the ratio of P/Q is equivalent to the R/S.
What is difference between Wheatstone bridge and Carey Foster bridge?
The construction of Carey Foster’s bridge circuit is similar to the Wheatstone bridge which consists of four arms in which four resistances are connected. Carey Foster’s bridge is a modification made on the Wheatstone bridge and it works on the same principle i.e., null deflection.
What is the principle of Carey Foster bridge in which condition Carey Foster bridge will be most sensitive?
Answer: It can be proved that the bridge is most sensitive when all the four Resistances are of the same order. In a meter bridge the Resistances of the two parts of the wire are of the same order as the unknown and known resistances are of the same order.
How do I increase the accuracy of my Carey Foster bridge?
Carey Foster Bridge Advantages The Carey Foster bridge is a modified form of the meter bridge in which the effective length of the wire is considerably increased by connecting a resistance in series with each end of the wire. This increases the accuracy of the bridge.
Why Carey Foster bridge is better than Wheatstone bridge?
In simple words, we can say that- Carey foster bridge is a bridge circuit that can calculate medium resistances or compare and measure two large/equal resistance values with small fluctuations. It’s a tweaked version of Wheatstone’s bridge circuit.
Why Carey Foster bridge is better than meter bridge?
What is end resistance in Carey Foster bridge?
The Carey foster bridge is used to measure the difference between two nearly equal resistances and knowing the value of one, the other can be calculated. In this bridge, the end resistances are eliminated in calculation. Which is an advantage and hence it can conveniently used to measure a given resistance.
What is the principle of Carey Foster?
The Carey foster bridge principle is simple and similar to Wheatstone’s bridge working principle. It works on the principle of null detection. That means the ratios of the resistances will be equal and the galvanometer records zero where there is no current flow.
What are the applications of Carey Foster bridge?
APPLICATIONS OF CAREY FOSTER BRIDGE It is used to measure the difference between the resistance. It can be used to find the specific resistance of the wire. It is used to compare the two equal resistances. It is used to measure the unknown resistance.
Which wire is used in Carey Foster bridge?
The Carey Foster’s bridge is as in the figure1. One meter long wire of manganin or constantan of uniform cross-section area is stretched along a meter scale. The wire is connected at both the ends with copper strips.
How Carey Foster bridge is better than meter bridge?
Why is copper strip used in Carey Foster bridge?
The connection between the resistors in the metre bridge is done using thick copper wires. Copper has very low resistivity. By using thick copper wires the resistivity is reduced further. Thick copper wires have a larger area and the resistance of wire becomes negligible.
When the Carey Foster bridge is more sensitive?
What is Carey Foster bridge method?
It is also referred to as the method of small resistances. The Carey foster bridge principle is simple and similar to Wheatstone’s bridge working principle. It works on the principle of null detection. That means the ratios of the resistances will be equal and the galvanometer records zero where there is no current flow.
How do you measure the resistance of a Carey Foster bridge?
The Carey Foster bridge. The thick-edged areas are busbars of almost zero resistance. In the adjacent diagram, X and Y are resistances to be compared. P and Q are nearly equal resistances, forming the other half of the bridge. The bridge wire EF has a jockey contact D placed along it and is slid until the galvanometer G measures zero.
How do you compare a Carey Foster bridge to a Wheatstone bridge?
A standard Wheatstone bridge for comparison. Points A, B, C and D in both circuit diagrams correspond. X and Y correspond to R 1 and R 2, P and Q correspond to R 3 and R X. Note that with the Carey Foster bridge, we are measuring R 1 rather than R X.
What are the advantages and disadvantages of Carey Foster bridge?
The advantages of Carey foster bridge are The complexity of the bridge circuit is reduced because there is no need for additional equipment except the slide wire and the resistances. It can be utilized as the meter bridge where the slide wire length can be increased by connecting resistances in series.