Smoothing capacitor

[Andrew Pollock]

Hi,
I'm using a transformer to lower UK mains electricity from 230Vac (50Hz) to 12Vac. I have got a rectifier (KBPC104) and will be using this to get around 12Vdc.

I would like to implement some smoothing to have a more constant dc supply. My load on the circuit I will be powering will be variable but will not exceed 1A. What value and type of capacitor should I use? How do I work this out for myself in the future.

I attached a drawing to help show my question.

 

[dr pepper]

They said a college 1 amp per 1000u as a rough rule of thumb, I'd be inclined to put one in as big as I could fit or want to pay for, do you have any lying around?

 

[Nigel Goodwin]

You need to be FAR more specific about your exact load - and throw away that absolutely appalling diagram, it's worse than useless.

 

[Andrew Pollock]

You need to be FAR more specific about your exact load - and throw away that absolutely appalling diagram, it's worse than useless.

Well that appalling diagram is all I have at the moment... But the circuit that I wish to power contains a motor (4.5V to 12V), a high op LEDagain 12V. The motor will be controlled by a pot. I really just need to try and find out the value of the capacitor that might hold the voltage to anything between 10.5V to 11.75V. Still at the ballpark stage here - naturally I will be refining everything as I go along but got to start some where.

 

[Andrew Pollock]

They said a college 1 amp per 1000u as a rough rule of thumb, I'd be inclined to put one in as big as I could fit or want to pay for, do you have any lying around?

Probably got loads of capacitors that would do the trick - a lot of my design will rely on trial and error. Thanks for the possible answer - ill give it a try and see what happens.

 

[ericgibbs]

Probably got loads of capacitors that would do the trick - a lot of my design will rely on trial and error. Thanks for the possible answer - ill give it a try and see what happens.

hi Andrew,
Look at this link https://www.electro-tech-online.com/tools/PSUCapV1.php

Its designed for a regulated power supply, but if you set Vreg drop out to 0V, it will give you a good indication of the output voltage.
E

 

[Styx]

Well specify your exact loading and how much ripple you are willing to tolerate and then choose the Farads around that (maybe L-R and some inrush control *IF* it gets large)

 

[ronv]

Read here before you start.

https://www.electro-tech-online.com/threads/power-supply-design-for-beginners.113613/