EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: little_carlos on September 14, 2015, 12:40:45 pm
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Hi, i was wondering about that yesterday and i hope you can answer this
since the relay inputs are activated with an electromagnetic field, does that magnetic field causes any noise or interference to any signal that goes through ?
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There can be some spikes if you are using stable DC to drive the solenoid but like a transformer with a thousand-turn primary and a one-turn secondary the noise is minimal.
However the real concern here is contact bounce which can be significant if you bought one with unsatisfying quality.
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If you are asking if there is any coupling of 'noise' from coil/magnetic field to the output contacts, then no, there is no realistic concern there.
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Hi, i was wondering about that yesterday and i hope you can answer this
since the relay inputs are activated with an electromagnetic field, does that magnetic field causes any noise or interference to any signal that goes through ?
Yes, repeat no.
In other words it depends on the type of relay, the operational environment, and the signal.
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In this very sensitive application, some precautions in the relay were taken to prevent noise :
http://electronicdesign.com/test-amp-measurement/whats-all-femtoampere-stuff-anyhow (http://electronicdesign.com/test-amp-measurement/whats-all-femtoampere-stuff-anyhow)
- shielding between coil and contacts
- reduced voltage range on the coil.