# Values for Full bridge rectifier L-RC circuit

#### PsySc0rpi0n

Joined Mar 4, 2014
1,773
Hello...

I was asked to build and analyse the waveforms of voltage and current for 3 circuits.

1st - Resistive Rectifier
2nd - Capacitive Load
3rd - LC Low pass filter

I did the 2 first ones but the 3rd one I'm not quite sure what values can I use for the L, C for a 10 Ω load (R). I'm also not sure what waveforms to expect. This is what I have just to start!

#### MrAl

Joined Jun 17, 2014
11,496
Hello...

I was asked to build and analyse the waveforms of voltage and current for 3 circuits.

1st - Resistive Rectifier
2nd - Capacitive Load
3rd - LC Low pass filter

I did the 2 first ones but the 3rd one I'm not quite sure what values can I use for the L, C for a 10 Ω load (R). I'm also not sure what waveforms to expect. This is what I have just to start!
View attachment 143105
Hi,

Are you allowed to use a simulator or do you have to calculate everything?
1N4148 diodes are high speed diodes not usually used for rectifiers, but if the current rating is good enough for your application you can get away with it i guess.
Looks like the frequency is only 50Hz for your application.

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#### PsySc0rpi0n

Joined Mar 4, 2014
1,773
I can use, and I'm using LTSpice to run simulations and eventually check analytic results with LTSpice.

#### MrAl

Joined Jun 17, 2014
11,496
I can use, and I'm using LTSpice to run simulations and eventually check analytic results with LTSpice.
Hi,

Oh ok that's cool.

How are you approaching the analysis?

With LTSpice you can experiment with the choke value to see how it affects the output voltage smoothness and peak currents in the cap for example.

#### ColinPatra

Joined Jan 27, 2018
28
Hi
Your simulation shops currents way over the limit of the diodes - but spice won't pick that up! And if the inductive filter is meant to smooth the waveform, the values are far too low, as you load current shows and voltage waveforms show. I think you will need a choke of the order of 1H and a corresponding increae in C.