Basics of Electrical Bridges

The electrical bridge contains two branches which are bridged from the center.

In this post, you'll learn:
  1. Configuration of Simple bridge (Wheatstone)
  2. Equations for the bridge
  3. Example to solve it
  4. Practical applications

Configuration & Equations

The simple configuration involves four resistors which are joined on two branches. The figure below better illustrates it:
We can use the Kirchhoff's voltage law in the lower loop to find output voltage:

An Example

Lets consider an input source of 12 V powers R1 = 5 Ω, R2 = 10 Ω, R3 = 7 Ω and R4 = 1 Ω. Now to find Vo:
Vo = 5.5 V

Practical applications

Let's consider the following condition for a moment:
Theoretically, the rations between resistors on both branches should be in equal ratio. For all cases where the above condition is satisfied the output voltage Vo goes to zero. And for such condition, the bridge is said as the balanced bridge.

The above case can be expanded to the temperature measurements where we can relate the output voltage Vo with the temperature changes.

So that was all about Electrical Bridges. Hope you learned a lot about Basics of Wheatstone bridge. So how are you going to use this knowledge in your field? Do write in comments.

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