Why is this happening (basic electronics help)

SoundsGood · 23 Nov 2012 at 23:41

Can anyone tell me why the lamp in the picture would flicker when the relay is in the off state? Have I wired it wrong?

Narj · 23 Nov 2012 at 23:45

Lizardmen.

malfunkshun · 23 Nov 2012 at 23:55

whats on the control side?

SoundsGood · 23 Nov 2012 at 23:58

It flickers even with nothing connected, I'm turning it on with the 5v output of an Arduino

Rotty · 23 Nov 2012 at 23:59

cos your relay is knackered

malfunkshun · 23 Nov 2012 at 23:59

I assume it isnt the relay in the picture?

PhillyDee · 23 Nov 2012 at 23:59

Probably because it is a solid state relay, instead of a mechanical one. Must have some voltage bleed!

SoundsGood · 24 Nov 2012 at 00:09

malfunkshun said:
I assume it isnt the relay in the picture?

It's the exact relay in the picture, brand new..

malfunkshun · 24 Nov 2012 at 00:21

I'd go with faulty or just low quality, try it with a much bigger load and see what happens.

SoundsGood · 24 Nov 2012 at 00:25

thanks, I'll try it with the boiler tomorrow if no joy back it goes.

coopersim · 24 Nov 2012 at 00:36

LED bulb? They sometimes flicker with a small amount of voltage that might be present

piggeh · 24 Nov 2012 at 01:05

It's a very small lamp, maybe get a bigger one?

bitslice · 24 Nov 2012 at 02:11

The load isn't big enough, or rather the SSR is incorrectly specified, you don't need a 45A device to control a lamp/boiler. It has a small leakage current in the off state which causes the flickering.

Also, it is incorrectly fused, you need a high speed fuse, not a dead sloth domestic plug type. Your SSR will happily burn to a crisp before that thing ever blows.

You see that RC snubber circuit on the SSR's label? That's why you are getting leakage current when you try to switch AC, the AC goes right through the capacitor.
If you have a 5Kohm 15W resistor handy, connect that in parallel with the driven load to act as a bleeder resistor.

The alternative is to pick a SSR that doesn't use a snubber, or as above, increase the load so the leakage current is irrelevant. Is there any reason why a mechanical relay won't do?

Tsk, lots of random guessing going on in the thread.

minister · 24 Nov 2012 at 02:36

Look like nazi torture, or what the israelis use on the arabs

Limpnoodle · 24 Nov 2012 at 07:35

you need to lick the connector's whilst they are on, gotta warm em up a bit, after that all should be fin!

SoundsGood · 24 Nov 2012 at 11:18

bitslice said:
The load isn't big enough, or rather the SSR is incorrectly specified, you don't need a 45A device to control a lamp/boiler. It has a small leakage current in the off state which causes the flickering.

Also, it is incorrectly fused, you need a high speed fuse, not a dead sloth domestic plug type. Your SSR will happily burn to a crisp before that thing ever blows.

You see that RC snubber circuit on the SSR's label? That's why you are getting leakage current when you try to switch AC, the AC goes right through the capacitor.
If you have a 5Kohm 15W resistor handy, connect that in parallel with the driven load to act as a bleeder resistor.

The alternative is to pick a SSR that doesn't use a snubber, or as above, increase the load so the leakage current is irrelevant. Is there any reason why a mechanical relay won't do?

Tsk, lots of random guessing going on in the thread.

Thanks, I should've asked you first

I'll try swap it for a lower rated one, it seems quite hard to find them with high speed fuses, maybe I'm searching for the wrong keywords

PhillyDee · 24 Nov 2012 at 11:20

SoundsGood said:
Thanks, I should've asked you first

I'll try swap it for a lower rated one, it seems quite hard to find them with high speed fuses, maybe I'm searching for the wrong keywords

Fast Blow / quick blow.