Hey everyone, I'm new here and was hoping I could get some help on something I've been trying to figure out.

Recently I read up on using a capacitive divider to make a simple PSU. I was wondering if anyone could confirm if the circuit I'm thinking of will work.

In general, it'd look like this:

Would this be feasible at providing +30V with upwards of 10A after rectification, and is there any safety issues I should be concerned with besides working with mains?

I plan to expand with fusing and further filtering if it's given the ok.

Thanks in advance,

-Drew

 

You dont need the 250 and 750uF capacitors, remove them. I would recommend you to use a center tapped transformer to have a bipolar power supply.

 

It is not a safe design. If the 250uF cap should short, the remainder of the circuit would be connected to the mains. Caps frequently short out when they fail.

You should use a transformer, or a "buck" design.

 

I would also replace the 10pf caps with much much larger caps. I would add regualtors after said caps.

 

It is not a safe design. If the 250uF cap should short, the remainder of the circuit would be connected to the mains. Caps frequently short out when they fail.

You should use a transformer, or a "buck" design.

What would you suggest for a buck design then that's capable of putting out +20V-35V and up to roughly 10A?

I'm trying to build a ~500W/channel class A/B amplifier and transformers for this are generally expensive and cumbersome. I know I've seen sub plate amps with even more power without transformers, so I know it can be done.

You dont need the 250 and 750uF capacitors, remove them. I would recommend you to use a center tapped transformer to have a bipolar power supply.

Actually, the goal there was to use reactive capacitance to provide a load and step AC down without the need of a transformer.

 

There are two strong disadvantages to using dividers to "step down" a voltage. One is waste. The other is a changing load can have a large effect on the desired voltage.

A much better use of dividers is for measurement - a negligible amount of power is needed and the load is fixed.