Introduction of DC Power Supply Ripple Measurement Instrument
oscilloscope
Oscilloscope is the main instrument for measuring the ripple of DC power supply. It can intuitively display the voltage waveform, making it easy to observe and analyze the ripple. The selection of oscilloscope should consider the following factors:
(1) Bandwidth: The bandwidth of the oscilloscope should be greater than the highest frequency of the measured signal to ensure measurement accuracy.
(2) Sampling rate: The sampling rate of the oscilloscope should be high enough to capture rapidly changing ripple signals.
(3) Input impedance: The input impedance of the oscilloscope should be large enough to avoid affecting the tested circuit.
AC millivoltmeter
An AC millivolt meter can measure the effective value (RMS) of ripple and is suitable for quantitative analysis of ripple magnitude. When choosing an AC millivolt meter, attention should be paid to its measurement range and accuracy.
Spectrum analyzer
A spectrum analyzer can measure the spectral distribution of ripples, which helps to analyze the sources and characteristics of ripples. When choosing a spectrum analyzer, attention should be paid to its frequency range and resolution.
Measurement steps for ripple of DC power supply
Prepare measuring instruments
Select appropriate measuring instruments, such as oscilloscopes, AC millivolt meters, etc., and calibrate them according to the parameters and requirements of the tested power supply.
Connect measuring instruments
Connect the measuring instrument to the tested power supply, taking care not to affect the normal operation of the power supply. The probe of the oscilloscope should be connected to the power output terminal, and the input terminal of the AC millivolt meter should be connected to the power output terminal.
Set measurement parameters
According to the parameters and requirements of the tested power supply, set the parameters of the measuring instrument, such as the time reference and vertical magnification of the oscilloscope.
Observe and record ripple
Turn on the power, observe the voltage waveform on the oscilloscope, and record the peak to peak value (Vpp) or effective value (RMS) of the ripple. If an AC millivolt meter is used, the effective value of ripple can be directly read.
Analyze ripple characteristics
Based on the measurement results, analyze the frequency, amplitude, and other characteristics of the ripple, and determine the source and influencing factors of the ripple.
Optimize power supply design
Based on the measurement results and analysis, optimize the power supply design, such as adjusting the filtering circuit, improving the switching frequency, etc., to reduce ripple.
