Application and Principle of Electric Bridge

Application field
Industry and scientific research: precise measurement of component parameters such as resistance, capacitance, inductance, etc., which is essential for electronic engineering and physical experiments
The cornerstone. In industrial production, it is used to detect the quality of electronic components and ensure stable product performance.
Sensor technology: In weighing sensors, strain gauges form a Wheatstone bridge to convert pressure or strain into electricity
Signal. The torque sensor also utilizes the principle of strain gauge bridge to measure the torque of rotating components.
Power and Communication: Used for testing the DC resistance of transformers and checking whether the winding connections are good. In the field of communication,
Measure antenna impedance and transmission line characteristics to ensure the normal operation of equipment.
Other fields: Measuring bioelectrical impedance in medicine to assist in disease diagnosis. AC bridge is also used to measure inductance
Capacitance and AC impedance

1、 The function of an electric bridge
The main function of the bridge is to measure the DC resistance of various devices with inductive characteristics, especially suitable for testing
Measurement of DC resistance of large power transformers and transformers; The measurement is simple, fast, and easy to operate.
Convert the resistance change rate Δ R/R of the resistor into voltage output, and then provide it to the amplification circuit for amplification
Measurement, it is a resistance measurement tool. There are two working modes of resistance bridge: single arm operation and double arm operation
Make it. In single arm operation, only one arm is connected to be measured, while the other three arms use fixed resistors; Working with both arms
In this case, if two arms of the bridge are connected to the measured object and the other two are fixed resistors, it is called a dual arm working bridge,
Also known as the half bridge form, if all four bridge arms are connected to be measured, it is called the full bridge form.
2、 The principle of electric bridge
Assuming four resistors are fixed, when S is closed, if the equation “R3 * R2=R1 * R4″ is satisfied, that is, the diagonal electric current
If the resistance product is equal, then Ucd is equal to 0, which means there is no voltage between cd. Using this principle, when the equation
When one of the four quantities on both sides is an unknown quantity, if adjusting the other three values can make the equation hold,
So the unknown quantity can be obtained using a formula.
But in reality, as long as there is an adjustable variable resistor on each side of the equation, then the other two resistors
If one is a fixed value, then the remaining one must be obtained. This principle can be used to make resistance measurements
Box, and this principle uses the concept of “bridge” or “balanced bridge”.