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Capacitor, 470nF, 400V connect directly to 220V/50Hz wall outlet?


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Mar 27, 2024
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Capacitor, 470nF, 400V connect directly to 220V/50Hz wall outlet?

I want to make a SMPS Power Supply circuit.

I want to examine part by part of the circuit separately.

Is it possible to connect this capacitor directly to 220V/50Hz wall outlet and
into the mass?

Circuit diagram:

Capacitor, 470nF, 400V, RM22.5, MKP, 10%

Related theme:
There in web shop is written that it is bopolar capacitor in category.

Capacitor, 470nF, 400V, RM22.5, MKP, 10%

A bipolar capacitor is just a non-polarized capacitor.
I think the term is usually in reference to a type
of electrolytic capacitor to make it clear that
you can use it in any orientation since they're usually polarized.

However I see that it is for dc voltage
• Voltage range: 160 – 2,000 VDC

I made mistake in buy.
The purpose of this non-polar plastic film capacitor is to be able to shunt high current from pulsed voltages. When these pulses are controlled on the load side with expected RMS current well below it's rating, this makes it overcome the higher impedance from inductive grid lines.

But it also exposes it to possibly dangerous shorts when over-stressed with spikes on the grid. Then the designer chooses something to raise the impedance used in SMPS line filters called a Balun or Common mode filter where X and Y rated similar caps are used like yours but designed to be self-healing if a breakdown occurs.

Bi-polar or bipolar is different and means two polar caps in one with reversed connections in series and are part of the electrolytic family not plastic film like yours.
There is no pole signed on the box but I understand it now.
Bipolar is for DC Voltage but it can be connected in any direction but
it must be connected just in DC voltage.

Is this capacitor regular for connecting in AC 220V/50Hz and into the mass?

There is notified:
Voltage AC: 400 V

In the link below:
MKS4 470nF 630V datasheet
There also written:
decoupling, energy storage, filtering
Last edited:
No, it has NOT been certified for the grid as follows;

• Approvals: ENEC, UL, cUL, CQC
• X2 CLASS (IEC 60384-14)

X & Y ratings means the design of the metal over film layers are either self-healing or fuses open circuit and not short circuit which may result in a fire.
As noted above, any capacitor placed directly on the mains should be X2 rated, i.e a self healing type rated for the peak stresses that often occur on a mains supply voltage.
I want to make this SMPS Power Supply circuit:

Can I use 275V AC X2 Is it enough?
in the scheme is mentioned 400V but is it related to 400V as
maximum voltage or as a strict for AC voltage?

I found some offers at local distributors.
What of these offers should I use for this circuit diagram?

Capactor, metalized polypropilene, MKP X2, 305V AC, 470nF, RM22.5, Wima

I found here:


Is it X2 series? X2 (MKP X2)?

Capacitor MKT Film WIMA MKS4 470nF 630V

Capacitor MKP Film WIMA MKP10 470nF 630V
This design does not include the essential details you need to choose all the parts called a bill of material or BOM and PCB layout.
Although it is simple and is an unregulated forward converter.

You will have a thousand questions like this when it doesn't work. A schematic is not enough to build a power supply until you do a lot of reading and get lab experience.

You need a parts list and PCB and EVERY part has a specific resistance {DCR, ESR, RdsOn} and many others that look to have the same value are not the same will not work.

I suggest you buy a kit to do this or a complete board from Banggood or similar if possible. It should have safety certificates.

--- Updated ---

for your interest,aps,138&sr=8-1
Last edited:
You are confusing me Tony. This started as a question about voltage ratings of a capacitor but you link to an advert for a 300W amplifier!

FWIW it was a reality check of make vs buy for modern AC powered power technology. The proposed schema was obviously power for audio BW
Because I am new is this good solution to buy

It would be dangerous for me as a beginner to experiment
with X2 capacitors and wall line.

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