A snubber is a circuit used to suppress transient voltages in electrical circuits. It can include RC snubbers that comprise a resistor and a capacitor in series, often used for AC circuits, and also a diode used across relays and other inductive components to suppress their inductive 'kickback'.

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How suppress bounce-related turn-on spikes in DC bench power supply?

I'm taking a refining pass on my DC Bench Power Supply design. It generally works quite well on veroboard, so I thought I'd move on to SMD PCBs and refine the design while working out a few of the ...
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216 views

Triac spurious triggering issue

I have a circuit where I am using triacs to switch home appliances like fan, tube light etc. This is the circuit I am using: (TRIAC1, TRIAC2, TRIAC3 come from arduino GPIO pins) First load is a ...
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133 views

AC SSR does not switch off - why?

I have a circuit meant to manage a shutter (or a shutter motor to be more precise). The motor has two power lines - depending on which power line one connects power, it moves up or down. I designed ...
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183 views

What is the thought process for specifying an EMI bypass cap on line transformer secondary?

Update It turns out I had mistakenly interpreted the role of the capacitor in question here as an EMI filter for line noise. It looks like a capacitor in that position actually serves as a snubber ...
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128 views

Best choice between flyback diode or an RC snubber

I have a motor that has a 24 Vdc (15 ohm) brake attached that tends to weld / burn up the contacts in the ice cube relay that controls it after a year or so. I was wanting to put some protection on ...
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181 views

Mosfet with capacitor across the load?

I'm designing this general purpose mosfet controlled output, and I'm used to putting D1 due to possibly inductive loads. However I was looking into some other implementations and this guy suggests ...
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260 views

Resistor in RC snubber

What is the purpose of resistor to suppress EMI? Couldn't I just use a suppression capacitor alone between the coil of the relay or contactor? I have tried to use capacitor alone and it did reduce EMI ...
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150 views

Flyback Transformer Active Snubber Design

I'm using a flyback transformer along with the LT3750 controller by Linear to charge a capacitor. I'm wanting to increase efficiency and improve the circuit. I began with looking into an RC snubber to ...
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34 views

Output capacitance of H-Bridge IC (DRV8432DKD) for snubber design

all. I have implemented a hydraulic pump driver circuit using a DRV8432DKD (36-HSSOP package). I provided pads for an RC snubber on my PCB, but I am having some trouble coming up with the values for ...
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150 views

Relay control of AC motors, handling turn-off kickback

I've been researching how to control a smallish AC-motor using a relay, and more specifically, how to turn an AC motor off using a relay. This is a subject that has been up many times at this site, ...
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304 views

Why not use only a MOV as a snubber for relay control of AC motor?

I'm building a circuit to control an AC motor using a relay. Since the motor is an inductive load, there will be a voltage spike when the relay opens. It seems that best practice for dealing with ...
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69 views

Snubber to protect a VO2223A optical triac switching 0.5A @24 vac?

Is a snubber necessary to protect a VO2223A optical triac to occasionally control a valve that draws .5 amp @ 24 vac 60 hertz. What would be the R/C values if required?
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147 views

RC snubber across switch or inductor

What are the differences one should consider between designing an RC snubber across a switch and across an inductor? Is there any preference for putting it across the switch?
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150 views

Is a flyback diode necessary when no sensitive chips are used?

I have had a look through all the information available about flyback or snubber diodes in a relay system and was hoping to confirm if one is necessary in my circuit or not. All the info about why a ...
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30 views

Confirming the use of a RIFA snubbing component across 120V relay switch

I have a mains relay switch (Packard C230B 2 Pole 30 Amp Contactor 120 Volt Coil) which allows me to turn on my pre-amp based on the existence of AC voltage on the amplifiers AC output plug (which is ...
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133 views

When are Avalanche-Rated MOSFETs Necessary?

Why do we care about avalanche rating for power MOSFETs in circuits that exhibit inductive kick (flyback converters, motor drives, etc.)? I understand the basic destructive mechanisms behind ...
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110 views

Are all snubbers interchangeale?

There are different kinds of snubbers that can be used. I know of 3, but there could be more. D RC RCD If an certain circuit uses a diode, can I swap it for an RC ? Or if a circuit has an RC, can ...
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5k views

How to calculate resistor and capacitor size for snubber circuits

I have a 24 VAC Contactor that I want to drive with a microcontroller through a photmos. How do I calculate the proper size resistor and capacitor for a snubber circuit? Here are some of the ...
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103 views

Help Identifying Capacitor

I was given the following capacitor by a spare parts shopkeeper when I asked for a polypropylene capacitor (to be used in RC snubber circuit for a mains load). Can someone confirm this is the right ...
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352 views

Can I use a TVS diode to remove spikes in SMPS?

I have an almost working Half-Bridge SMPS that has some ringing in the output like this (not the real output, just and image I found): I have eliminated almost all the oscillation using a snubber ...
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545 views

Should I use a snubber or solid state relays on a 24 vac circuit?

I'm trying to create a smarter controller for my hydroponic systems. I have an arduino controlling a sainsmart mechanical relay. The load on the relays are 24 VAC orbit sprinkler valves. Everything is ...
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843 views

Mosfet Snubber with Inductive Load

I am designing switch circuit that switches on and off a relay that switches on and off a 115AC light.So the switching speed is not a concern as it is a once in a while on or off. The relay for the ...
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880 views

Snubber causing more problems than benefits

When designing and building a simple motor controller i used 2 snubber circuits, one to protect the main triac and another one the smooth the communication between the phototriac and the main triac. ...
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348 views

Triac motor controller

I have build a circuit with the purpose of driving a ~1000VA AC motor. The motor controller fires a triac only at zero crossings. The circuit is as follows: simulate this circuit – ...
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824 views

Relay protection with MOV and RC Snubber

I am going to build a protection circuit for a 240 volt pump motor. It is believed that when the relay cuts out the motor generates voltage back into the relay and burns out the contacts. It has ...
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599 views

Is ceramic capacitor suitable for snubber?

Is there any Problem to put a ceramic capacitor (0.1nf/2kv) in a snubber circuit.
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How to protect the switching device from back EMF when we connect the inductive load

Why the snubber circuit is necessary for inductive load and not for resistive load. What is the back EMF?. When we connect the inductive load how the back emf affect the switching device. how to ...
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How to calculate Snubber for different load value

We are doing home automation project in that we need snubber for both resistive and inductive load. If we connect less than 5W load(Bulb) it is keep on glowing without switch on. Whether i ...
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538 views

will snubber pass voltage thourgh it?

We are doing home automation project. In that we are using triac for ac switching and snubber circuit (R=100ohm, c=10nf) for its protection. Here we have inductive and resistive load, for inductive ...
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5k views

Reducing LED PWM Noise: Which is the best option?

Driving an LED with a microcontroller should be easy. But when looking into noise, things can get complex... As an instantaneous voltage indicator used in a variable power supply (which will be used ...
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3k views

Using an RC snubber with a triac. Is this design safe? (simulation included)

I'm designing an ac switch for a washing machine motor. No speed control is intended, only a switch to turn the motor on for 10 seconds and off for 10 seconds. I'm using a MOC3063 zero-detecting triac ...
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485 views

Routing the circuit for a snubber diode on a PCB?

I understand that the "ideal" place for a snubber diode is across the terminals of the inductive device that generates the flyback. But in the interest of making my PCB design for an Arduino shield as ...
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310 views

Questions about RD snubber circuits

I am not too familiar with designing snubber circuits. Can somebody sanity check the following sizing calculation for a snubber circuit? Also: Is the undampened rise rime of the voltage due to the ...
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1k views

How to design a snubber for optotriac

I've seen in several places this snubber circuit composed of 2.4K and C1 in this particular case. My question is - what's the purpose of this network exactly and how are the values for the ...
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Choosing TRIAC snubber resistor for multi-purpose switching

I'm designing a circuit to switch a 240V AC load and haven't done a lot with AC power control before. I'm planning to use a Fairchild MC3043-M optically coupled TRIAC driver along with a BT138-600 NXP ...
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How to design an RC snubber for a solenoid relay driving an inductive load?

I read up that switches driving inductive loads need to be snubbed and an RC pair seems to be the best (cheapest?) option. I have a large-ish AC induction motor (for a refrigerant compressor) that is ...
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Flyback diodes issues and pull-in & hold current issues in this Relay circuit

Although this may be a basic question but I'm still struggling with it. In this schematic, two zener diodes D1 and D2 are connected back-to back across relay coil L1. The BVds = -30V for Q1. Can I use ...
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394 views

Is this part (given picture) an EM relay, relay-controller, snubber?

Here is a rather bad (low resolution, grainy) picture of a circuit board that claims to be a 2-channel 315MHz ASK/OOK type remote controlled relay set. I can identify the relays, but not the big blue ...
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2k views

Optotriac doesn't turn off

I'm using an opto triac, specifically the MOC3041, with a zero crossing circuit to switch the Tx pinout on an RS-232 interface. I have no problems turning it on, but after I unload the input (no ...
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3k views

Snubber design for switching an inductive mains load with a relay

I am envisaging a relay which switches an inductive load consisting of a couple of switched-mode power supplies (standard ATX computer power supplies) in addition to several wall-wart style power ...
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8k views

Choosing components for a triac's snubber

I'm interfacing the BT139-600 TRIAC with this MOC3051-M Opto-triac. I want to build a snubber circuit for the TRIAC as shown in the MOC3051M opto-triac's datasheet @ page 8, figure 12. The load ...