What are the similarities and differences between the double arm bridge and the Wheatstone bridge?

1. Differences:

1. Different organizational structures:

Wheatstone bridge is also called single-arm bridge, and only one of the bridge arms is the resistance to be measured;

The resistance to be measured in the double-arm bridge is actually connected to the two bridge arms.

2. The functions are different

Wheatstone bridges are mainly used to measure median resistance (generally greater than 1 ohm and less than 1m ohm); The double-arm bridge and the two arms are stretched out to use the resistance connected to the voltage connector to divide the voltage, so if the current connector is inward, the measured resistance and contact resistance are measured, so it is larger.

Dual-arm resistors are mainly used to measure low-value resistance (less than 1 ohm). Because the Wheatstone bridge has eliminated the influence of the internal resistance of the meter on the circuit, and the influence of the wire resistance and contact resistance on the circuit should be reduced when measuring the low resistance resistance, the Wheatstone bridge has been improved to a Kelvin double-arm bridge.

2. Similarities:

1. The function is the same: they are all instruments used to accurately measure resistance.

2. The structure has a bridge arm, that is, resistance, and the change of resistance is used to measure the change of physical quantity.

The double-arm bridge is used to measure the low resistance, because the Wheatstone bridge has eliminated the influence of the internal resistance of the meter on the circuit, and when measuring the low resistance value resistance, the influence of the wire resistance and contact resistance on the circuit should be reduced, so the Wheatstone bridge has been improved into a Kelvin double-arm bridge. Because there is no diagram to illustrate the principle, you can only characterize your problem: because the arms of the double-arm bridge are stretched out and use the resistance connected to the voltage connector to divide the voltage, so if the current connector is inward, the measured resistance and contact resistance are measured, so it is larger.

As mentioned in J*121, the double-arm bridge cleverly transfers additional resistors such as contact resistance and lead resistance into the internal resistance of the bridge power supply, and attaches them to the bridge arm with relatively large resistance values, so that when the bridge is balanced, the influence of these additional resistors on the measurement results is eliminated, and the measurement accuracy is improved. Therefore, it is suitable for low resistance measurements (less than 1 ohm, such as the resistance of a shunt in an ammeter).

1. The structure is different. The Wheatstone bridge is also called a single-arm bridge, only one of the bridge arms is the resistance to be measured, while the resistance to be measured in the double-arm bridge is actually connected to the two bridge arms.

2. The application is different. Wheatstone bridges are mainly used to measure median resistance (generally greater than 1 ohm and less than 1m ohm), while double-arm resistors are mainly used to measure low resistance (less than 1 ohm).

Wheatstone Electrification Dashi BridgeThe principle is that there is a resistor with an unknown resistance value, and a variable resistance with a known resistanceResistors, resistance, and roll. In a circuit, connect the two series circuits in series, and then connect the two series circuits in parallel, connect a wire at the midpoint of the wire between and and the midpoint of the wire between and and with the middle point of the wire between and and connect a wire, and place a galvanometer on this wire.

At that time, there will be no current flowing through the wire in the middle. Since the presence of current is very sensitive, Wheatstone Bridge can obtain fairly accurate measurements.

Wheatstone Bridge is a measuring tool invented by Samuel Hunter Christie in 1833 and improved and popularized by Charles Wheatstone in 1843. It is used to measure the resistance of unknown resistors in the fine nuclear group, and its principle is similar to that of the original potentiometer.

1. Different structures: Wheatstone bridge is also called single-arm bridge, and only one of the bridge arms is the resistance to be measured; The resistance to be measured in the double-arm bridge is actually connected to the two bridge arms.

2. Different applications: Wheatstone bridge is mainly used to measure median resistance (generally greater than 1 ohm and less than 1m ohm), while double-arm resistance is mainly used to measure low resistance (less than 1 ohm resistance).

3. Different influencing factors: the single-arm bridge will be affected by the external circuit resistance, while the double-arm bridge will exclude the influence of the external circuit resistance.

The similarity is that they both use the principle of bridge balancing.

Whiss leather pants on the bridge.

It is a bridge circuit composed of four resistors, which are called the bridge arms of the bridge.

Wheatstone bridges use changes in resistance to measure physical quantities.

changes in single-chip microcomputers.

It is a highly accurate measurement method that collects the voltage at both ends of the variable resistor and then processes it to calculate the change of the corresponding physical quantity. Conditions for bridge equilibrium: The product of the resistance of the bridge relative to the arm is equal.

Bridge Concept: An instrument that measures various quantities (e.g., resistance, capacitance, inductance, etc.) using a comparative method. The simplest circuit is a circuit consisting of four branches. Each branch is called the "arm" of the bridge.

Wheatstone BridgeThe way to form a bridge is: to adjust WheatstoneBridge balancingThere is a way to do it.

The resistance of the four bridge arms on the opposite side is multiplied, and the equality of the opportunity is the equilibrium condition, and the adjustable resistance of one of the bridge arms in the version is adjusted, and the weight current is measured, the current is zero, and the bridge is in a balanced state (except for the other two points at the power-up end are connected to the ammeter.

Resistors R1, R2, R3, and R4 are called the four arms of the bridge, and Hu Fang G is a galvanometer to check whether there is current in the branch where it is located. When g passes through without current, the bridge is said to be balanced. In equilibrium, the resistance of the four arms satisfies a simple relationship that can be used to measure the resistance.

Unbalanced bridges.

It is generally used to measure small changes in the value of the balance resistance, e.g. by applying a resistance strain gauge.

The resistance wire is made into a grid and pasted between two layers of tissue paper or plastic film to form a solid object, when the object is deformed, the strain gauge is also deformed, the resistance of the strain gauge is changed from Rx when the bridge is balanced to Rx+ R, then the current Ig through the galvanometer will also change, and then R can be measured according to the relationship between Ig and R, and then the deformation of the object is calculated by the relationship between R and the solid pants.

It is composed of a power supply, a switch, and a galvanometer bridge arm resistor.