Since DC stabilized power supply is generally formed by AC power supply through rectification and stabilization, it is inevitable that there are some AC components in the DC stabilized quantity. The AC component superimposed on the DC stabilized quantity is called ripple. The composition of the ripple is more complex. Its shape is generally a sinusoidal harmonic with a frequency higher than the power frequency. The other is a pulse with a narrow width. For different occasions,
the requirements for ripple are different. For the good capacitor, no matter what kind of ripple, as long as it is not too big, it will not affect the quality of the capacitor. For the power supply used in programmable control machine or audio equipment, there is not enough energy for the narrow pulse to drive the speaker's cartridge or the receiver of the microphone to form a murmur. Therefore, the requirement for this narrow pulse can be relaxed. For the sinusoidal ripple signal in the audio range, although its amplitude is not too high, its energy makes the speaker or the receiver hum. Therefore, there should be certain requirements for this kind of ripple, and for some control occasions, because the narrow pulse will interfere with the digital or logical control components at a certain height, which will reduce the reliability of the equipment operation, so the amplitude of this narrow pulse should be limited.
For the similar sinusoidal ripple, 1. Generally, because of its low amplitude, there is little interference to the control parts. The expression of ripple can be expressed by effective value or peak value, absolute quantity or relative relative quantity. For example, a power supply operates in a steady state, its output is 100V5A, and the effective value of the measured ripple is 10mV. This 10mV is the absolute quantity of the ripple, while the relative quantity is the ripple coefficient = ripple voltage/output voltage = 10mv/100V = 0.01%, which is equal to one in ten thousand.
The ripple coefficient, in short, is the peak value of the AC component in the DC voltage. Ripple is an AC component of DC voltage. DC voltage is supposed to be a fixed value, but in many cases it is obtained through AC voltage rectification and filtering. Because the filtering is not clean, there will be residual AC components. Even so, power supply with batteries will produce ripple due to load fluctuation. In fact, even the best reference voltage source device has ripple output voltage. To experience, you can use an oscilloscope to see the voltage fluctuation, like the ripple, so it is called ripple. In general, the AC millivoltmeter is used to measure the ripple voltage, because the AC millivoltmeter only responds to the AC voltage, and its sensitivity is relatively high. It can measure very small AC voltage, and the ripple is often relatively small AC voltage. If there is no AC millivoltmeter, the oscilloscope can also be used to measure. The input of the oscilloscope is set as AC coupling, and the Y-axis gain is adjusted to make the waveform size appropriate. The magnitude of the ripple voltage can be estimated by reading out the voltage value. The ripple voltage will affect the work of the system and bring noise. So the power supply should have enough filtering measures to limit the ripple within a certain range.
Kingrun DC winding resistance tester, DC power supply ripple coefficient is controlled within five ten thousandths to ensure that the test results are accurate and reliable.