Suggest other better methods of measuring resistance?

Answer 1

There are several methods for measuring resistance, each suited to different situations and levels of precision. Here are the most common methods:

Ohmmeter: This is the most common method for measuring resistance. An ohmmeter is a device that directly measures resistance. It typically consists of a voltage source, an ammeter, and a variable resistor. When connected to a circuit, it passes a known current through the component whose resistance is being measured and then measures the voltage drop across it. The resistance is calculated using Ohm's Law (R = V/I), where R is resistance, V is voltage, and I is current.

Multimeter: A multimeter combines several measurement functions into one device, including voltage, current, and resistance. Most modern multimeters have a setting for measuring resistance (Ohms), and they function similarly to standalone ohmmeters.

Bridge Circuits: Bridge circuits, such as Wheatstone bridge, are used for precise resistance measurements. They compare the unknown resistance with a known resistance in a balanced bridge circuit. The bridge is adjusted until there is no current flow through the detector, indicating that the bridge is balanced. Then, the resistance of the unknown component can be calculated based on the known resistances and the bridge configuration.

Kelvin Bridge: A Kelvin bridge is a modification of the Wheatstone bridge and is used for accurate measurement of low resistances. It eliminates the resistance of the connecting leads by using four terminals instead of two.

Meters and Galvanometers: Galvanometers are sensitive instruments that measure small currents. By applying a known voltage across the unknown resistance and measuring the resulting current using a galvanometer, the resistance can be calculated.

Digital Methods: Modern digital techniques use microcontrollers or specialized integrated circuits to measure resistance. These methods often offer high accuracy and precision.

Resistance Temperature Detectors (RTDs): RTDs are sensors whose resistance changes with temperature. By measuring their resistance and knowing their temperature coefficient, you can indirectly measure temperature.

Four-Wire Measurement: Also known as Kelvin sensing, this technique is commonly used to measure very low resistances accurately. It eliminates errors caused by the resistance of the connecting wires by using separate pairs of leads for current and voltage sensing.

Each method has its advantages and is suited to different applications, ranging from simple household measurements to precise laboratory measurements.