Snubber Circuits on the power switch? Pros and Cons

[pavlo_y0l0s]

ESP has a nice article talking about RC snubbers over the relay contacts. Even though switch is not a relay but it is similar in operation.

Section 4.2

Relays Part 2

DIY Audio from ESP - relays, what they are and how to use them.

sound-au.com

“There are some 'rules of thumb' that are applied to snubbers used across contacts, and these give the designer a good place to start. The following fall into that category - this isn't meant to be the only range of values that can be used, but you have to start somewhere ...

R1 - 0.5 to 1Ω per contact volt
C1 - 500nF to 1 µF per contact amp

For example, if you wanted to switch 48V DC at 10A, R1 could be 24Ω, and C1 would be around 20µF. If AC is being switched, the series impedance of R1 + C1 must be large compared to load impedance, or current will be delivered to the load even when the contacts are open. Because AC is less troublesome than DC, the capacitance value can be reduced considerably, and I'd suggest that C1 would only need to be around 1µF at the most. “

 

[Speedskater]

Remember that AC power line snubbers need to be safety listed (UL).
The hard part is getting into the appliance to install them.

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