CA6240 micro ohmmeterMainly used to measure the DC resistance within its range, suitable for measuring the resistance of contact points such as metal conductors and wires, as well as the resistance of motor and transformer windings. This product is an ideal measuring instrument with high measurement accuracy, stable performance, clear display, wide measurement range, and strong anti-interference ability. It has a beautiful appearance and easy operation.
CA6240The working principle of micro ohmmeter:
The working principle of a micro ohmmeter is based on the four wire method measurement of the bridge principle, which applies a constant current to both ends of the resistor, measures the voltage at both ends by the instrument, and then automatically calculates the resistance value through the instrument. Its advantage is that the measured data is close to the true resistance value of the working state, eliminating the influence of the resistance of the test line itself.
Ordinary multimeters usually use the proportional method to measure resistance. The measured resistance is connected in series with the standard resistance. Measure the standard resistance and the voltage of the measured resistance. The currents of the two are the same. Measure the resistance of a resistor by converting the resistance of a standard resistor. The actual measurement circuit also uses the corresponding voltage of the standard resistor as the reference voltage, so that the voltage at both ends of the measured resistor can be directly measured.
Therefore, when measuring micro resistance, a milliohmmeter or micro ohmmeter can better reflect the actual resistance value. The resistance of the multimeter test line will affect the true value of the measured resistance. For example, when measuring a resistance of 1 ohm, if the test line of the multimeter itself is 1 ohm, the displayed resistance is 2 ohms. Do you think this resistance is real? But milliohmmeters and micro ohmmeters do not have this problem.
The Kelvin test method is an impedance or voltage measurement technique that uses separate current and voltage detections, allowing for more accurate measurements than traditional dual ended (2T) sensing. The main advantage of four wire detection is the separation of the current application unit and the voltage measurement unit, which eliminates wiring impedance and contact resistance.