Choosing a Multifunction Multimeter
The basic principle of a multimeter is to use a sensitive magneto-electric DC ammeter (microammeter) as a meter head. When a small current passes through the head, a current is indicated. However, the head can not pass large currents, so some resistors must be connected in parallel and series on the head for shunt or voltage reduction, so as to measure the current, voltage and resistance in the circuit.
1. Temperature measurement: In electronic maintenance, the multimeter with this function is convenient for you to check the degree of heating of electronic components, such as welding and pulling components, measuring temperature to prevent damage to components.
2. Simultaneous measurement: AC and DC components in electronic testing, we encountered the signal is not very pure AC or DC signals, we need to observe the total true RMS value of the waveform (including AC and DC parts) in order to analyse the amount of power consumption of the circuit to find out part of the parts of the burned out cause of the DC out of tune.
3. dBm and millivolt value measurement: the so-called dBm value measurement, i.e., low level measurement ----dB value measurement. dB is generally expressed by this formula: dB = 20LogV measurement / V reference. If change V reference voltage, through the test comparison, we can measure the corresponding value: for example, used to analyse the voltage gain of the voltage generator.
4. Spike hold: the use of multimeter true RMS measurement, we can measure the width of this function is greater than 0.25 milliseconds of the width of the instantaneous peak voltage of non-regular AC signals, and automatically maintain, conducive to the search for the cause of destruction of components and equipment.
5.△ Relative Value Measurement: Using this function, we can carry out relative value measurement, i.e. the difference between our test voltage or current and the reference voltage or current, and the capacitance relative mode can clear the stray capacitance in the reading.
