Diode in AWS circuit

[Amrutha]

Can you please clarify the purpose of Diode in AWS circuit?

[Peter]

Can you please clarify the purpose of Diode in AWS circuit?

By its very nature, the AWS magnet is highly inductive. Basic electicial principles will tell you that when you try to break the current which feeds it, the change in flux in the magnet will generate a voltage (which can easily be higher than the supply voltage) of the opposite polarity. This has a tendancy to cause arcing on the relay contacts.

The diode is provided across the supply and is reverse biassed for the normal supply voltage (ie it is effectively open circuit). Given that the back emf is reverse polarity, the diode conducts the current generated after the feed contacts open effectively shorting out the circuit and helping to reduce the back emf to zero as quickly as possible, minimising damage from arcing.

Put "back emf" in your favourite search engine to get explanations and demonstrations like this.

[Amrutha]

Thanks peter..

Can you please clarify the purpose of Diode in AWS circuit?

By its very nature, the AWS magnet is highly inductive. Basic electicial principles will tell you that when you try to break the current which feeds it, the change in flux in the magnet will generate a voltage (which can easily be higher than the supply voltage) of the opposite polarity. This has a tendancy to cause arcing on the relay contacts.

The diode is provided across the supply and is reverse biassed for the normal supply voltage (ie it is effectively open circuit). Given that the back emf is reverse polarity, the diode conducts the current generated after the feed contacts open effectively shorting out the circuit and helping to reduce the back emf to zero as quickly as possible, minimising damage from arcing.

Put "back emf" in your favourite search engine to get explanations and demonstrations like this.