Differences Between Megohmmeters and Multimeters
1. Different composition structures:
A megohmmeter is composed of medium to large scale integrated circuits. This table has high output power, high short-circuit current value, and multiple output voltage levels (each model has four voltage levels).
A multimeter consists of three main parts: the meter head, measuring circuit, and conversion switch.
2. The working principle is different:
A megohmmeter measures resistance by exciting the device or network under test with a voltage, and then measuring the current generated by the excitation using Ohm's law.
The basic principle of a multimeter is to use a sensitive magneto electric DC ammeter (microampere meter) as the meter head. When a small current passes through the meter, there will be a current indication.
3. Different usage ranges:
A megohmmeter is a commonly used and essential instrument in industrial sectors such as power, postal and telecommunications, communication, electromechanical installation and maintenance, as well as the use of electricity as industrial power or energy. It is suitable for measuring the resistance values of various insulation materials and the insulation resistance of transformers, motors, cables, and electrical equipment.
A multimeter can not only be used to measure the resistance of the object being measured, but also to measure AC and DC voltages. Even some multimeters can measure the main parameters of transistors and the capacitance of capacitors.
Testing function of digital multimeter
The digital multimeter can not only measure DC voltage (DCV), AC voltage (ACV), DC current (DCA), AC current (ACA), resistance (Ω), diode forward voltage drop (VF), transistor emitter current amplification factor (hrg), but also measure capacitance (C), conductance (ns), temperature (T), frequency (f), and has added buzzer mode (BZ) and low-power method resistance mode (L0 Ω) for checking circuit continuity. Some instruments also have the functions of inductance mode, signal mode, AC/DC automatic conversion, and capacitance mode automatic range conversion.
Most digital multimeters have added the following novel and practical testing functions: HOLD, LOGIC, TRMS, REL Δ, AUTO OFF POWER, etc.
