Pointer multimeter frequency measurement method
To measure frequency using a multimeter, you can convert the frequency to a voltage to measure it. Some newer pointer multimeters have a frequency measurement function. It should be noted that if you want to measure frequency, you must convert the measured frequency into a DC voltage signal to complete the frequency conversion.
Here we will introduce a frequency measurement method. This method uses a pointer multimeter (DC millivolt meter with a full scale of 200mV) and a frequency/voltage converter. Suspicious measurement of 10Hz ~ 20kHz range of frequency, measurement accuracy of up to 2%, the measured frequency signal RMS value of 50mV ~ 10V.
I. Measurement principle
Firstly, the frequency/voltage converter is used to convert the measured frequency signal into DC voltage, which is then sent to the 2.5V voltage gear. Measurement circuit shown below, the circuit mainly contains operational amplifier TL061, CMOS six inverter CD4069, CMOS timer ICM7555.
Among them, IC1 acts as a voltage amplifier, IC2 plays the role of shaping and buffering, and IC3 constitutes a frequency/voltage converter.
How to measure AC contactor A1 and A2 voltage with a multimeter under energised state
Use the multimeter AC voltage 500V gear directly connected to A1 and A2 can be
Select the multimeter AC voltage gear 750V gear, look at the jack position, black black pen to com. red pen to V jack, red and black pens were placed on both ends of the A1A2, measured voltage value
The multimeter will be played to the highest grade, according to the display down! If the pointer type must be done, the pointer should be in the middle position, such as digital electronic table, the purpose of reducing the measurement error, but also to reduce to the appropriate file!
With a multimeter AC voltage file, 250v file (estimated voltage 220v) or 500v file (estimated voltage 380v) measurement. Connect both pens to the A1A2 terminals and watch the reading.
Simple enough to say the question off the top of your head without thinking about it, first use Ac high level to measure and see if the resultant value is not working or not right then use Dc high level to measure it
Directly with the multimeter playing in the 600V voltage gear, with the pen on the line, AC power without positive and negative poles, the pen to measure the A1 and A2, with or without power at a glance!
First determine the known end voltage to be measured, the vast majority of factory power ≤ 380V AC, civilian are 220V AC, set the multimeter AC 500 volts, direct measurement can be!
