High resistance resistance measurement experiment report

In electronic circuit design and testing, high resistanceresistanceAccurate measurement is of great significance to ensure the stability of circuit performance. Due to the large resistance of high-resistance resistors, direct measurement is prone to environmental interference and instrument limitations, resulting in large errors in measurement results. Therefore, carrying out high-resistance resistance measurement experiments and exploring effective measurement methods and precautions is particularly critical to improving measurement accuracy and experimental reliability. This article will combine the experimental process and elaborate on the measurement principle, instrument selection, experimental steps and precautions.

High-resistance resistors usually refer to resistors with a resistance above megaohms (MΩ), and their measurement mainly relies on the voltage-current method (Ohm's law). Due to the large resistance value, the current flowing through the resistor is extremely small, making it difficult to accurately measure with a traditional ammeter. Highly sensitive current measuring instruments or indirect measurement techniques such as the bridge method must be used. In the experiment, the resistance value is calculated by applying a certain voltage, measuring the voltage across the resistor and the weak current flowing through it.

Instrument selection is particularly critical when measuring high value resistors. Commonly used equipment includes high resistance meters (megohmmeters), digital multimeters (with high resistance measurement function), bridge instruments, and high input impedance voltmeters. In the experiment, instruments with high input impedance, high measurement accuracy and strong anti-interference ability should be selected to avoid errors caused by the instrument itself.

High resistance resistance measurement has high environmental requirements. The laboratory should be kept dry and dust-free to avoid humidity and dust from causing leakage current on the resistor surface and causing measurement errors. At the same time, it should be kept away from strong magnetic fields and electromagnetic interference sources to ensure the stability and accuracy of measurement data.

Properly designed measurement circuits can effectively reduce errors. In experiments, a voltage source and a high-precision current detector are usually used in series to connect the resistance to be measured to ensure voltage stability and sensitive current measurement. The circuit should avoid the influence of contact resistance and lead resistance, and the measurement accuracy can be further improved by using the four-wire measurement method (Kelvin measurement method).

(1) Connect the measurement circuit and ensure that the wiring is correct and the contact is good.

(2) Adjust the voltage source output and apply appropriate voltage to avoid resistor damage caused by excessive voltage.

(3) Use a high-sensitivity ammeter to measure the weak current flowing through the resistor.

(4) Record the voltage and current data and calculate the resistance value.

(5) Repeat measurements multiple times and take the average to reduce accidental errors.

Experimental data should be processed reasonably, average values ​​and standard deviations should be calculated, and measurement stability should be evaluated. Error sources mainly include instrument accuracy limitations, environmental interference, contact resistance and temperature changes, etc. Through error analysis, targeted improvement measures can be taken, such as increasing shielding, improving contact methods, calibrating instruments, etc., to improve measurement reliability.

(1) Avoid damage to resistors and measuring instruments caused by electrostatic discharge.

(2) Keep your hands clean when measuring to avoid the influence of human body charges.

(3) Use shielded wires and grounding measures to reduce interference.

(4) Disconnect the power supply promptly after the experiment to prevent the resistor from being damaged due to long-term high voltage.

Accurate measurement of high-value resistors is an important issue in the field of electronic testing. By rationally selecting instruments and equipment, optimizing measurement circuits, strictly controlling the experimental environment and standardizing operating procedures, measurement errors can be effectively reduced and accurate and reliable resistance values ​​can be obtained. This article provides a practical reference for related electronic experiments and applications through a systematic introduction to high-resistance resistance measurement experiments, helping to improve the measurement technology level and experimental quality. In the future, advanced instruments and automation technology can be combined to further improve the efficiency and accuracy of high resistance resistance measurement.