Skip to main content

X Rated Capacitor

Pin Configuration

The X Rated Capacitors has no polarity. Meaning they can be connected in any direction.


X Rated Capacitor Features

  • Metallized Polyester Film Capacitor
  • Self-healing property
  • Excellent electrical characteristics
  • Flame retardant epoxy resin coating
  • RoHS directive compliant


X Rated Capacitor Specifications

  • Category temp. range (Including temperature-rise on unit surface) - 100 VDC, 250 VDC,400 VDC, 630 VDC, 1000 VDC, 1250 VDC is –40 °C to +105 °C
  • Category temp. range (Including temperature-rise on unit surface)- 125 VAC, 250 VAC-- –40 °C to +85 °C
  • Rated voltage is 100 VDC, 250 VDC, 400 VDC, 630 VDC, 1000 VDC, 1250 VDC, (Derating of rated voltage by 1.25 %/°C at more than 85 °C) 125 VAC, 250 VAC
  • Capacitance range is  0.0010 μF to 10 μF (E12)
  • Capacitance tolerance is ±5 %(J), ±10 %(K)
  • Withstand Voltages are

             Rated voltage 100 V to 630 VDC

             Between terminals: Rated voltage (VDC)✕150 % 60 s

             Rated voltage 1000 VDC, 1250 VDC

             Between terminals: Rated voltage (VDC)✕175 % 2 s to 5 s or 1000 VAC 60 s

             Between terminals to enclosure: 1500 VAC 60 s

             Rated volt. 125 VAC, 250 VAC

             Between terminals: Rated voltage (VAC)✕230 % 60 s

             Between terminals to enclosure: 1500 VAC 60 s


Brief about X Rated Capacitors

The X rated capacitors are one of the different types of capacitors. They come in 100 VDC, 250 VDC, 400 VDC, 630 VDC, 1000 VDC, 1250 VDC,125 VAC, 250 VAC electrical rated voltage. They comes in the capacitance ranging 0.0010 μF to 10 μF broadly. The 400 VDC rated capacitor comes in the capacitance range of 0.010 to 0.10 μF and 0.12 to 0.47 μF.

These capacitor comes in Non-inductive construction using metalized polyester film with flame retardant epoxy resin coating. The have special features of self-healing property along with high electrical ratings makes them suitable for high voltage applications.


Identifying Ceramic Capacitors

How To Select A X Rated Capacitor

Capacitance value is given in code value.

Example: 0.010μF has code of 103, 0.47μF has code of 103 474, 0.1μF has code of 104.

Also rated voltage code can be seen in the above figure for different AC and DC voltages.


How to Use a X Rated Capacitor In Transformer-less Power Supply

X rated capacitors comes with high voltage ratings can be used directly in series with the AC mains.

The main component of a Transformer-less power supply circuit is Voltage dropping capacitor or X-rated capacitor, which are specially designed for AC mains. This X rated capacitor is connected in series of Phase line of AC, to drop the voltage. The transformer is replaced by Dropping capacitors. 

How To Select A X Rated Capacitor in Transformer-less Power Suply

Bridge rectifier is used to convert the stepped down AC signal into DC signal. Zener diode is 1N4733A 5.1V .Zener diode is used to generate a regulated DC output. Capacitor  47uF/6VDC is a Smoothing Capacitor is used to generate ripple free DC. LED is used to indicate the DC output.

Selection of voltage dropping capacitor is important, it is based on Reactance of Capacitor and the amount of current to be withdrawn.

The Reactance of the capacitor is given by below formula:

    X = 1 / 2πfC

    X = Reactance of Capacitor

    f = Frequency of AC

   C = Capacitance of X rated capacitor

We have used 0.47µF capacitor and frequency of AC mains is 50 Hz so the Reactance X is:

   X = 1 / 2*2.14*50*0.47*10^-6 = 6775.98Ω

Now we can calculate the current (I) in the circuit:

   I = V/X = 230/212.40= 33.9434 mA 

So that’s how the Reactance and Current is calculated.

The above transformer-less power supply is only suitable for compact circuits with low current ratings.

Note: The Circuit has direct handling with the AC voltage. Precautions are to be taken while dealing with direct AC voltage. Insulation at the AC voltage wires is recommended. Do not Replace X Rated Capacitor with the normal capacitors



  • Capacitive Power Supply or Transformer-less Power supply


2D Model Representation

2D Model Of X Rated Capacitor

Related Post

Join 20K+subscribers

We will never spam you.

* indicates required

Be a part of our ever growing community.