Reducing AC noise in PSU

[neazoi]

Hello,
How can I reduce the AC noise in an AC PSU? (50-60Hz transformer connected to mains).
A common mode can be used in the output as well?
What if I connect a capacitor (non-polarized) accross the AC line?

 

[Kuldeepluvani]

Generally to reduce ac current distortion you can use a inductor also known as chock or reactor. It creates back electromotive force(emf) or voltage as current passes through it and reduces current spikes.

 

[neazoi]

Generally to reduce ac current distortion you can use a inductor also known as chock or reactor. It creates back electromotive force(emf) or voltage as current passes through it and reduces current spikes.

What, you mean a choke in a PI configuration at the output, or a common mode choke at the input?

 

[FlapJack]

neazoi, are you talking about audible noise or high frequency electrical noise.

 

[D.A.(Tony)Stewart]

100 or 120 Hz ripple is hard to reduce without bulky high ripple current RLC filtering on the rectified side.

It s generally expensive if low noise is required, thus active regulators are preferred although inefficient but less ripple current ratings required. SMPS are an obvious advantage.

 

[neazoi]

neazoi, are you talking about audible noise or high frequency electrical noise.

Since the PSU is mainly goind to be used in RF, I think HF noise performance is more important.

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100 or 120 Hz ripple is hard to reduce without bulky high ripple current RLC filtering on the rectified side.

It s generally expensive if low noise is required, thus active regulators are preferred although inefficient but less ripple current ratings required. SMPS are an obvious advantage.

Ok so apart from the common mode chokes/varistors/discharge tubes at the mains side, there is nothing else that can be done to reduce the noise so that the psu can be clean for RF?

 

[D.A.(Tony)Stewart]

Since the PSU is mainly goind to be used in RF, I think HF noise performance is more important.

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Ok so apart from the common mode chokes/varistors/discharge tubes at the mains side, there is nothing else that can be done to reduce the noise so that the psu can be clean for RF?

RF Amps have poor PSRR in general. Have you considered a linear Regulator with RF caps and ground plane?