The reason why multimeters have bandwidth
In the world of measuring instruments, digital multimeters are the most commonly used. Digital multimeters measure objects (voltage, resistance, capacitance). What we are going to talk about today is the bandwidth of the multimeter for measuring voltage. The bandwidth unit is expressed as (hertz: the English representative is Hz). The bandwidth indicates the frequency bandwidth that the device can effectively and accurately measure. Generally speaking, the bandwidth is -3db bandwidth, -20log (output voltage/input voltage) = -3db (the base of log is 10), which can be calculated: input voltage/output voltage = 0.7; the multimeter is accurate for 20Hz signal response When the voltage is gradually increased, the output will change due to the different response characteristics of the multimeter to signals of different frequencies. At a certain frequency, the output voltage = 0.7 times the input voltage, which means that the signal has reached the -3db bandwidth of the multimeter.
Why does a multimeter have bandwidth?
The first method is: when we measure current, it is easiest to measure the bandwidth model. When the engineer adjusts the switch to the current position, one side of the protruding black and red wires is connected to the incoming signal line, and the other side is connected to the input signal line. Observe the current change. If there is a value, it means there is a signal, otherwise there is no signal.
The second method is: Electricians can creatively use the current level to detect the current between two wires of the network cable (one dark color, one light color). If there is current in all four groups, there is a signal, otherwise there is no signal. .
Among the many multimeters, the bandwidth of the Fluke multimeter depends on the factors of different multimeter models (basic characteristics, readings, true RMS, DC accuracy, etc.) to determine its bandwidth results. Generally there are (20KHz to 100KHz) ranging.
