# Circuits Calculus design

## Main Question or Discussion Point

Circuits Calculus design!!

Hey Everybody!!

i have always wonder how do you calculate complex circuits!!!....i mean, when you`re in college they teach you how to solve by Nodes, kirchoff, thevenin and norton Resistive circuits and RLC circuits......but after that they never teach you how to calculate and design your own circuits....

my question is....how do you calculate the values of the components in a complex circuit???

for example, check this circuit of a voltaje regulator.....how do you calculate its values???

thanks!!

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This is a common design of a power supply.

C1 and C2 filter out the 60 Hz ripple voltage which is there and could ruin your power supply.

To kill the ripple voltage, you need to short the AC as much as you can, and still allow DC to pass.

How do you calculate reactance of a capacitor?

And what value of capacitance do you think would represent the lowest impedance (meaning a short)

Since there is a voltage regulator you have to look up the manufactures data sheet LM350 to get the formula for Vout in terms of R1 and the potentiometer. Sometimes they are empirical.

D6 and D7 prevent any reverse voltage damaging LM350. The circuit will still work without these diodes. But this is well designed power supply, so they are there as a precaution.

C3 and C4 further filter out the ripple. BUT

If you are designer, you have to foresee the impossible. What if a high frequency signal gets fed into the output is this power supply? You would want to short it out also. What value of C4 would use?