What is the difference between a megger and a multimeter or multi-function meter?
1, the structure is different:
Megohmmeter consists of medium and large scale integrated circuits. This meter has high output power, high short-circuit current value and many output voltage levels (each model has four voltage levels).
The multimeter consists of three main parts: meter head, measuring circuit and transfer switch.
2, the working principle is different:
Megohmmeter uses ohm's law to measure the resistance by exciting the device or network under test with a voltage and then measuring the current generated by the excitation.
The basic principle of multimeter is to use a sensitive magnetoelectric DC ammeter (microammeter) as the meter head. When a small current passes through the meter, there will be a current indication.
3, the use range is different:
Megohmmeter is a common and essential instrument for electric power, post and telecommunications, communication, electromechanical installation and maintenance, and industrial enterprises that use electric power as industrial power or energy. It is suitable for measuring the resistance of various insulating materials and the insulation resistance of transformers, motors, cables and electrical equipment.
Multimeter can be used to measure not only the resistance of the measured object, but also the AC and DC voltage. Even some multimeters can measure the main parameters of transistors and the capacitance of capacitors.
On-off principle and standard of multimeter
When the multimeter is set to the on-off position, the internal circuit that is connected is: the black stylus is connected to the negative electrode of the internal battery, the positive electrode of the battery is connected to a resistor with a small resistance, and the other end of the resistor is connected to a red stylus. The internal calling circuit gets the trigger signal from the resistor. If the two probes are short-circuited or the resistance between them is small, the voltage on the trigger resistor in the meter is high, thus triggering the chirping. If the resistance between the two probes is large, then the partial pressure of the internal trigger resistor in series is small, and the chirping cannot be triggered.
