What decides the value of capacitor used in power supply?
The value is 2200 microfarad.
Please also suggest some books for understanding capacitors from the basics.
I think this application report from Texas Instruments may help you: www.ti.com/lit/an/slta055/slta055.pdf
Hi Avinash,
Your capacitor is the energy storage of your power supply. I assume you are talking of a full bridge rectifier followed by a capacitor, then regulated. Basically, it should be large enough to provide a nearly constant voltage. Still, you will have some ripple, that is the consequence of the load pumping some energy. This ripple should be within a band (call it DV), if you have an idea of what the current consumption is then you can relate DV to C, the current I and half a period of the rectified voltage T by C*DV=I*T/2 (the 1/2 is because it's full bridge).
Mind you, this calculation holds in this case (you did not mention the type of power supply, nor the frequency) but the idea is there.
The value of a power supply capacitor also affects the ESR (as does the electrolytic, such as commonly-used aluminum). Low ESR is critical for a power supply. Google provides answers and links for your question and should always be your first resource. For example, a simple introduction to ESR and how the capacitance affects it is at http://www.illinoiscapacitor.com/pdf/Papers/low_ESR_fact_or_fiction.pdf.
The value of capacitor mF depends on your application.
If you are using this for PF improvement then your present kvar-targetted kvar will decide the amount of KVAR needed ,from that KVAR=Rt3*VISin phi,then you get the Xc from this Xc=1/2*3.14*C
A capacitor before a circuit forms a low-pass filter with the input resistance of that circuit . the cut-off frequency of that filter is (1/RC) where R is the input resistance of circuit and C is the capacitance. so if you want to filter all noises and just have the DC signal you must increase RC. The R value is dependent on the circuit and usually you can not change it but you can increase C value to lower the cut-off frequency. This is why the capacitor value should be large.
The input capacitor is decided in reference with output power derived from the power supply and ripple voltage allowed in the switch voltage. output capacitor is decided wrt the load current and transient load delivery.
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