Hello,
I am new to Arduino and electronics, and I am also a slow learner and not particularly good reader so, I followed a tutorial about connecting relay (SRD 5VDC SL C) to Arduino UNO,
When I connected it to the board on pin 5 and set it HIGH and LOW id made "tick" sound and red led also worked,
I connect LN to pin 5, GND to GND and VCC to 5V onboard.
Now I tried to connect desk lamp to it, 60W, 220V.
it has 2 wires one is split so I connected one part to NO and one part to GND (middle) (also tried to connect 1 part to NC)
and tried to test it again, now it not make "tick" sound anymore even if I disconnect the lamp
but leds still works and turns on and off.
Is it possible that I broke my relay somehow? or something?
You need to make a pencil drawing showing all the connections and post a photo of the drawing. Verbal descriptions of wiring are too easy to misunderstand.
Post a link to the datasheet for the relay.
DO NOT PLAY WITH 220V when you do not know what you are doing. It might work for you and then fail for your wife or son or sister and kill them.
Desk lamp, you only wanted to cut 1 wire, and connect the two loose ends to NO and C. The other wire is left intact.
When the relay energizes, NO & C connect and let current flow thru the lamp.
Yes I know this and that exactly how I connected it.
But the problem now is that the relay not seem to work anymore, its not make the sound of magnet activation.
The relay itself is a simple relay, but your drawing shows it on a relay control board that has an led, diode, and probably a switching transistor to control power to the relay coil. That is the item for which we need more information.
A stand alone relay would not need 5 volts, just a command signal and ground. But the coil does funny things to the circuit along with the fact that the arduino does not supply enough current to directly drive a relay of any size, so you need either a relay board or a circuit that looks like this.
Well it tells me that the relay can be used with 240vAC up to 7A on a resistive load but apparently only 120v on an inductive load. Is your lamp a resitive load?
However it is quite possible that the board the relay is attached to is not rated for 240v or 7A - so you need the datasheet for the actual product you are using - not just for one of the components.
The symptoms suggest welded contacts, but a 60W lamp should not be able to do that
to a 10A relay. Something is definitely wrong somewhere. Is it a fluorescent lamp?
Old style ceiling-mounted fluorescent strips are highly inductive and that would explain it,
but you said desk lamp...
Have you (with no mains connected) tried investigating the voltage across the relay coil
when trying to operate it? It no voltage there, then the coil driver is blown. If voltage there
then either the coil winding is blown or the contacts are welded.
Was this relay board a cheap chinese import? I would certainly not trust such on mains. Always
use genuine UL-rated parts in mains installations - the risk to life and limb from using questionable
components is not worth it.
and tried to test it again, now it not make "tick" sound anymore even if I disconnect the lamp
If the problem persists after using an adequate power supply for the relay board, then the relay contacts have welded closed. With all power turned off, take the handle of a screwdriver and tap the casing of the relay (all sides and top) ... this will usually free up the contacts and bring the relay back to life. Tapping too hard (of course) could break the relay (which it already is).
To reduce relay contact arcing, try using a ferrite core on the AC load wire. This can be a quick and effective solution. In this case, disconnect the load wire that goes from the relay's (COM terminal in your case) and wrap it through the ferrite core with 5 or more turns (the more the better). Re-connect the wire. Now the arcing will be greatly reduced, the relay will last longer and the interference problems should go away.
NoobCube:
is it possible that the lamp had too much power or something and it damaged the relay?
Not too much power, but enough to weld the contacts closed if there's no arc suppression. With incandescent load, should only use up to only 10% of the relay's switching power capacity.
dlloyd:
If the problem persists after using an adequate power supply for the relay board, then the relay contacts have welded closed. With all power turned off, take the handle of a screwdriver and tap the casing of the relay (all sides and top) ... this will usually free up the contacts and bring the relay back to life. Tapping too hard (of course) could break the relay (which it already is).
To reduce relay contact arcing, try using a ferrite core on the AC load wire. This can be a quick and effective solution. In this case, disconnect the load wire that goes from the relay's (COM terminal in your case) and wrap it through the ferrite core with 5 or more turns (the more the better). Re-connect the wire. Now the arcing will be greatly reduced, the relay will last longer and the interference problems should go away.
