Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

[SOLVED] relay using back-emf

Status
Not open for further replies.

josh1245

Newbie level 5
Joined
Oct 20, 2012
Messages
10
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,355
hello..

I am using a relay which works with 230 v AC supply (its a 230V solenoid).. so with back-emf, what more can i add in order to protect the circuit??
please help me. Its urgent. :idea:
 

Im sorry about it. But the problem is that, i am using a PIC16F877A micro-controller, so when i need, I would use a relay to switch to a circuit containing a 230V solenoid, so beause of this, i think a huge back emf will be generated , therefore i would like to know a solution to this..
 

Use a diode as mentioned by Tahmid.

A snubber is also a good idea.
 
Last edited:

A snubber circuit, resistor capacitor, in series connected in parallel to relay coil terminals.
 

Switch relay at zero-crossing point. That will reduce EMI-noise, and lifetime of relay coil will increase.

- - - Updated - - -

hello..

I am using a relay which works with 230 v AC supply (its a 230V solenoid).. so with back-emf, what more can i add in order to protect the circuit??
please help me. Its urgent. :idea:

I reading previous posts, I think people forgot this relay have working coil on 220V AC.

- - - Updated - - -

That HV relay should be switched with smaller relay which is connected to uC pin over transistor, and also have flyback diode over coil. I want to say you need some kind of isolation. Also check SCR zero cross detection switching,...
 
  • Like
Reactions: FvM

    FvM

    Points: 2
    Helpful Answer Positive Rating
If the relay coil is driven from 230VAC, you can't use a single anti-parallel diode. That is only for DC. For AC, you need to use an RC snubber. You can also use back-to-back transils/transzorbs/transient suppressors. There are quite a few transzorbs that have two back to back built inside. You may take a look at the P6KE and the P15KE series.
 

hey everyone! thanks verryyy much... your ideas really gave me some help.. um working on it now...
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top