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What is a safety capacitor? What is its type and usage?


For what reason do we really want a safety capacitor? probably because of the word “safety”and It is a capacitor that meets safety certification compared with ordinary capacitors. The Safety capacitor protects the safety of the circuit, and after the capacitor is damaged and fails, the circuit of the safety capacitor will not endanger our personal safety.

The Safety guidelines have clear articulations and direction on the hardware and electronic parts, to keep away from electric shock, energy (fire/bend/blast), fire, radiation, mechanical and warm/high temperature, mishaps and catastrophes like compound dangers, because of unfortunate plan or inappropriate use. They expect makers to furnish clients with protected and great items to safeguard the lives and property of clients and administrators.

What is a safety capacitor?

The safety capacitor is a high-voltage, circuit-explicit capacitor that is related to the safety of the circuit and the human body and has passed the safety certification. The safety capacitor can suppress the electromagnetic interference of the power supply and protect the customer from electric shock when the capacitor fails.

Safety capacitors are surprisingly generally utilized and not just by power hardware engineers. For instance, everything with an EMI-channel on board has Safety capacitors integrated into that circuit. There are as yet many designers out there that have barely any familiarity with these significant parts since they don’t really utilize them themselves.

What’s the type of safety capacitor?

X capacitor

X capacitors are capacitors that are connected between the two power supply lines(L-N). The most common of the X capacitors are the x2 safety capacitors, and possibly the X1 capacitors that are used in some very high voltage circuits.X capacitors generally use UF grade metal film capacitors to suppress differential mode interference.

Customary capacitors have low wave current and high unique inward opposition. So in the event that we utilize common capacitors rather than X capacitors, the wave current file is additionally hard to meet the prerequisites. As per genuine necessities, the capacitance of X capacitor is permitted to be bigger than that of Y capacitor. In addition, the X capacitor also has the functions of suppressing electromagnetic interference, stepping down the resistance and capacitance, and acting as a DC filter.

X-type safety capacitors are divided into three types according to withstand voltage: X1, X2, and X3. The peak pulse voltage overvoltage level allowed in the safety level of safety capacitors: 2.5kV<X1≤4.0kV, X2≤2.5kV, X3≤1.2kV .

Y capacitor

The Y capacitor is the capacitance between the power line and the ground line. Different from X capacitor, Y capacitor usually chooses NF capacitors and basically appears in pairs to suppress common-mode interference.Y capacitor, otherwise called the “line to ground capacitor” or “the line sidestep capacitor” — the capacitor set among line and ground — flops short, this could prompt a lethal electric shock because of the deficiency of the ground association.

Class-Y Safety capacitors are intended to bomb open. A disappointment will make your electronic gadget be exposed to the clamor and obstruction that the capacitor would ordinarily sift through, yet essentially there will be no deadly electric shock risk.

Y-type safety capacitor safety grade: Y1≥250V, allowable peak pulse voltage>8KV; 150V≤Y2≤300V, allowable peak pulse voltage>5KV, Y4<150V, allowable peak pulse voltage>2.5KV.

What are safety capacitors used for?

Safety capacitors are for the most part utilized for power supply gulfs. At the information end of the air conditioner power supply, three Safety capacitors are added to stifle EMI conduction obstruction. They are utilized in power channels to channel familiar mode and differential mode impedance.

The Safety capacitor has an enormous wiggle room for the breakdown voltage. Assuming the ostensible voltage of the Safety capacitor is just 400V or lower, its endure voltage is no less than 1000V, so separating is troublesome.

The role of the capacitor is to pass high impedance and low impedance, pass high frequency, and resist low frequency. The larger the capacitance, the easier it is for low frequencies to pass, and the larger the capacitance, the easier it is for high frequencies to pass. In addition, filtering is an important part of the function of safety capacitors, which are used in almost all power circuits. When safety capacitors are specifically used for filtering, large capacitors (1000uF) filter out low frequencies, and small capacitors (20pF) filter out high frequencies.

What’s the application of safety capacitor?

What's the application of safety capacitor?

Capacitors are fundamental uninvolved parts utilized in each cutting edge circuit and gadgets application for smoothing and separating electrical cables and for bypassing signals. In AC/DC EMC channel applications, two exceptional classes of capacitors – Class-X and Class-Y – are utilized to channel AC power-source clamor and are ordinarily alluded to “somewhere safe capacitors”.

Significant market sections for Safety capacitors keep on being in power supplies, lighting stabilizer, AC power connector, car DC engine applications, smoke alarms and other line voltage hardware.

What is the difference between X and Y capacitors?


● The x capacitor is the capacitor across the two lines (L-N) of the power line, and a metal film capacitor is generally used. The y capacitors are capacitors connected across the two power lines and ground (L-E, N-E), usually in pairs.

● Due to the restriction of the leakage current, the value of the Y capacitor should not be too large.

● Generally, the X capacitor is of uF level, and the Y capacitor is of nF level.

● The x capacitor suppresses differential mode interference, and the Y capacitor suppresses common mode interference.

● Most of the X capacitors have a square shape similar to a box; most of the Y capacitors are oblate and blue in color.

How do I test a safety capacitor?


Safety capacitor is a sort of capacitor that won’t influence the human body regardless of whether it comes up short. In view of its superior presentation, it has turned into a promoted item among capacitor items and is profoundly preferred. Notwithstanding, testing is a fundamental interaction for the buy or utilization of Safety capacitors.

A few techniques are utilized to test the safety capacitor using multimeter
● Capacitance mode on the multimeter
● Resistance mode on the multimeter
● Voltmeter to test a capacitor
● Multimeter continuity mode
● Check the capacitor outwardly for issues

How do I choose a safety capacitor?

Safety capacitors are natural to us, and we frequently see them in exchanging power supplies. In any case, numerous fledglings don’t have the foggiest idea how to pick one for use. The accompanying enlightens you concerning the sort choice. In the first place, you can track down a proper Safety capacitor producer, and it’ll furnish you with a choice book.

In the event that you do not know how to decide, you can converse with the specialized staff, and he/she will give the suggested Safety capacitor model. Or on the other hand you can apply for an example test to track down a reasonable Safety capacitor.

Do safety capacitors have polarity?

The extremity of a safety capacitor rely upon its sort and its have two sorts, captivated and non-polarized.A non-polar safety capacitor is one that has no irrefutable limit and can be used in either heading in a circuit. A polarized safety capacitor has a natural furthest point, meaning it may very well be related in one course in a circuit.

FAQ about safety capacitor

Most frequent questions and answers

Safety capacitors refer to safety capacitors that will not cause electric shock and will not endanger personal safety after the capacitor fails. Safety capacitors are usually only used for filtering in anti-jamming circuits. They are used in the power supply filter to play the role of power supply filtering, and filter the common mode and differential mode interference respectively. For safety and EMC considerations, it is generally recommended to add a safety capacitor at the power inlet.

The X capacitor is a capacitor for X2 (X1/X3/MKP) to suppress the electromagnetic interference of the power supply, and it is a capacitor connected across the two lines (L-N) of the power line. Generally, the main functions in the circuit are: power supply cross-line circuit, EMI filtering.

Y capacitors are capacitors connected across the two lines of the power line and the ground (L-E, N-E), usually in pairs. The main function of the Y capacitor is to suppress common-mode interference, which can filter out the coupling capacitance of the primary winding and the secondary winding.


In spite of the fact that there are Safety capacitors in the power supply now, you don’t have to stress a lot over spillage and harm to the human body, however you actually need to focus in your regular routine, particularly assuming you have kids at home. Youngsters are exceptionally dynamic and inquisitive. Take a defensive measure on the power supply or put the power attachment where kids can’t contact it so they are liberated from any prospects of risk.

There are many sorts and models of capacitors available. While buying Safety capacitors, as well as focusing on whether there is Safety confirmation on the body of the Safety capacitor , you ought to likewise focus on whether the Safety capacitor maker you pick is reliable.

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