47μF100V capacitors are generally aluminum electrolytic capacitors. This type of capacitor has poor high frequency performance and unstable capacitance. Electrolytic capacitors with a withstand voltage of 100V are generally large in size. Such capacitors are generally used in circuits. High-voltage filter capacitor or coupling capacitor.
Although some ultra-low frequency oscillation circuits or timing circuits use 47μF electrolytic capacitors, the working voltage of such circuits is generally low. Even if 47μF electrolytic capacitors are used, electrolytic capacitors with such high voltage resistance will not be used, because When the capacitance is the same, the higher the withstand voltage value of the general electrolytic capacitor, the larger the volume.
This kind of 47μF/100V electrolytic capacitors are commonly used in filter circuits and coupling circuits with higher power supply voltages. In the RC step-down LED drive circuit shown in the figure above, generally a filter capacitor of tens of μF is connected in parallel at both ends of the LED lamp beads. If the drive circuit drives a dozen white light LED lamp beads in series, the filter capacitor C2 Generally, filter capacitors with a withstand voltage of 100V are used, and most of their capacity is 10-47μF.
In addition, if the high voltage AC amplifier in some measuring instruments adopts resistance-capacitance coupling, 47μF/100V electrolytic capacitors are generally used.
