# Series capacitance inquiry 120vdc bridge rectifier, smoothing capacitor

Discussion in 'General Electronics Chat' started by bneuberger, Sep 16, 2016.

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1. ### bneuberger Thread Starter New Member

Sep 16, 2016
2
2
hello this is my first post ever to a forum so I apologize if I skip some vital information.
I have made 120v full wave rectifier circuit to drive 10 x 7.5ohm 12vdc led strips.
The circuit is arranged into 5 x 15ohm 24vdc pairs of led strip lights averaging .5amps per pair about 50watts, all in series to average the 120vdc input. I am currently using 1500uF smoothing caps per pair of LED strips, But due to the charging curve it is outputting close to 30vdc per led pair.
I'm using the capacitance formula for delta voltage but I'm unsure if I set the delta voltage in the equation to say 6volts if my new farad calculation would actually lower the output voltage effectively. By six volts I mean the lowest point in the ripple, I'm not sure if the RMS would give me only a 3v drop in reality. I've thought about it so much I'm going in circles.

.5A*.008/6 = 670uF per 24vdc .5a series branch

I understand that I could just add an additional 12v circuit to get the desired voltage but having a corrected capacitor value is better for my intended use.
The resistor in the schematic is just to show the resistive load of the lights, not an additional resistor. I was originally calculating an RC value until I read of the smoothing capacitance formula.

There is a 4a fast blow fuse of the ac input not shown in the schematic...

Thank you in advance! I'm sure you have better things to do than educate me on basic electronics, however the knowledge you share here could help educate me to help others in the same fashion.

2. ### AlbertHall Well-Known Member

Jun 4, 2014
2,262
448
I think this is a circuit for driving LEDs from the mains and discussion of such circuits is not allowed on this forum.

3. ### bertus Administrator

Apr 5, 2008
15,799
2,386
Hello,

In the User Agreement there is given that leds to mains are not allowed.

Bertus

4. ### bertus Administrator

Apr 5, 2008
15,799
2,386
Hello,

The thread is closed due to a void of the user agreement.
When you want to ask something, post in the feedback forum

Bertus