# how to calculate the Vo(dc) of a fullwave bridge rectifier with n smoothing capacitor? and also how to find the smoothing capacitor value?

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the Vo(dc) of a fullwave bridge rectifier with n smoothing capacitor? and also how to find the smoothing  capacitor value?

#12299

 Tip: It is possible to build your power supply without adding a regulator, when you want to power up an electrical motor, a small ripple in voltage will not affect the performance, unlike the electronic circuits and devices!

Designing of +12v 5A Power Supply:

To calculate the voltage required and the transformer secondary winding we first determine the input voltage for the regulator, which is 15v, plus a 10% of this value for ripple. For a regular transformer we have to consider a bridge rectifier, as a result; we will add 1.4v. So the secondary winding should be 15+1.5+1.4=18.9 lets say 18v @ 5 Amps. Now we will calculate the capacity of the filtering capacitor. By using equation number 1 and assuming that f=60Hz, we will get C=5 x 5 / ((18-1.4) x f) =25,100µF

#12300

The main function of power supply is to convert AC to DC; as shown in fig 1, the first stage is to make full wave rectifier to the AC signals by using bridge rectifier, filter the rectified wave by using filtering capacitor and finally select the appropriate voltage regulator to generate pure DC signal.

Current rating for bridge rectifier should be suitable with load current, also; the designer should consider the voltage drop across each diode, which is normally equal to 0.7v. Note that only two diodes are required when usingcenter-tapped transformer.

The following formula is used to calculate the capacitance value for the filtering capacitor: . . . (1)

C: Capacitor value.
Vp: Peak voltage. (“Bridge output max voltage”)
f: Frequency of the AC supply.