Usually connected between VCC and the ground, the capacitor provides a low impedance path that allows the AC components in the DC power line to pass to the ground.
Where are the capacitors located on a power supply?
When we look at almost any power supply application circuit there will be capacitors on the output of the power supply located at the load. One question often asked of power supply vendors is “Why are the output capacitors required on a power supply and how are the capacitors selected?”.
Why are capacitors placed across power supply terminals?
Based upon our discussion it should now be understood that capacitors are often placed across the power supply terminals at the load to reduce the voltage excursions caused by load current transients and the finite bandwidth response of the power supply.
It cannot give much current to drive inductive loads and since it is connected directly to mains, capacitor breakdown can damage the load. Moreover, there is the risk of shock hazards, if handled carelessly. If properly designed and constructed, the capacitor power supply is compact, light weight and can power low current devices.
What happens if a capacitor is plugged into a power supply?
The capacitor will charge rapidly at a rate determined by the maximum current of your power supply, the ESR of the capacitor, and any parasitic L/R, whereupon it will act as an open circuit, with no further current flow. Depending on your power supply, you might trip the overcurrent protection.
Why does a capacitor spark when connected to a power supply?
You will probably see a spark if you are connecting the capacitor to a live supply. The capacitor will charge rapidly at a rate determined by the maximum current of your power supply, the ESR of the capacitor, and any parasitic L/R, whereupon it will act as an open circuit, with no further current flow.
It is fine to connect them when the output voltage of the supply and the voltage across the capacitor are close to each other. If they are not close to each other, you may get a spark at the moment you connect them. The spark can suprise you with the amount of energy it delivers.