fourresistor

The term fourresistor refers to a circuit consisting of four resistors connected in various ways to form a resistive network. These networks are among the simplest multi-component configurations and are used in measurement, signal conditioning, and educational demonstrations.

The most well-known fourresistor topology is the Wheatstone bridge, a diamond-shaped arrangement in which four resistors connect to the four corners of a diamond, and a detector is connected across the two opposite corners. The bridge is balanced when the ratio R1/R2 equals the ratio R3/R4, in which case no current flows through the detector and the input impedance is determined by the resistor ratios rather than absolute values. This property makes Wheatstone bridges useful for precise resistance measurements and sensor calibration.

Other common fourresistor configurations include a square loop with a resistor on each side, and a two-branch ladder where two resistors are in series in each branch and the branches are in parallel. The equivalent resistance depends on topology; for the two-branch ladder, R_eq equals ((R1+R2)(R3+R4)) / ((R1+R2) + (R3+R4)).

In practice, fourresistor networks are used in device sensor interfaces, attenuators, and educational experiments to illustrate concepts such as balance, series-parallel reduction, and network equivalence. They are analyzed with Ohm’s law and network theorems, often using nodal or mesh analysis.

History and terminology: The Wheatstone bridge, developed in the 19th century, popularized the use of a fourresistor network for precise measurement; its principle remains foundational in resistor network theory and instrumentation. See also Wheatstone bridge and resistor networks.