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'.
Questions tagged [snubber]
199 questions
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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 being switched by a solenoid relay (about once…
Sohail
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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 BT138-600 TRIAC. Referring to the following…
PeterJ
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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 driver and a BT137-600E triac. This circuit was…
hadez
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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 15V(Vz = 15V) zeners for D1 and D2 instead of…
jacks
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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 specifics. Thank you for your help!
Microcontroller - 5V…
Superheat
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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 to simulate a photovoltaic array of a student's…
svilches
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Snubbing DCM (nonsynchronous) Buck converter
FINAL UPDATE:
I've posted an outcome report below. I'm very satisfied with how this has come out and I learned a lot in the process. More details and before/after shots in the answer below. Thanks to @Andy and @winny for their help and encouragement…
scanny
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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 resistor and capacitor calculated?
Does it provide a…
miceuz
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Is this snubber needed for MOSFET?
I met this kind of snubber network in Switchmode Power Supply Handbook (by Keith Billings and Taylor Morey):
They were using it with BJTs, and the reason was to limit dv/dt to avoid secondary breakdown of the BJT. Now if I'm using MOSFET in a…
U.L.
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Snubber Capacitor Voltage Rating in the Real World
What are voltage ratings for the capacitors inside the common off the shelf ac snubber networks, such as 0.1uF + 100 Ohm ?
It would seem that larger inductive loads can easily drive the capacitor voltage into the kilovolts. Is it ok because it only…
mcu
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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 fan with a capacitor based regulator. (Sorry for…
Whiskeyjack
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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 for high-frequency rectifier switching spikes/noise.…
scanny
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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 this voltage spike is to connect a capacitor across…
avl_sweden
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How do you calculate RC snubber values for a discrete bridge rectifier
I'm working on a small linear power supply for an audio amplifier (home/hobby use) and I want to add an RC snubber on the rectifier diodes. I know this might be overkill, but I'm looking at it as an educational endeavour as well (I'll build a…
CatalinM
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Do ferrite beads need snubbing diodes?
Inductors, when applied as inline power filters, need a parallel snubbing diode so that when the load opens, the current can be safely discharged.
In certain contexts, ferrite beads such as the Laird 28L0138 series can be used as inline power…
Reinderien
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