Snubber circuit for this Circuit.

[kurrodu]

The circuit below works fine as long as there are two power supplies, one for the micro controller and one for the relay.

However, I would like to use a single 5v power supply for the pic controller and the relay. I need a snubber circuit so that the controller does not hang due to emi generated from the relay. I need a snubber circuit. Load on the relay is 230V, 30Watts.

 

[ericgibbs]

The circuit below works fine as long as there are two power supplies, one for the micro controller and one for the relay.

However, I would like to use a single 5v power supply for the pic controller and the relay. I need a snubber circuit so that the controller does not hang due to emi generated from the relay. I need a snubber circuit. Load on the relay is 230V, 30Watts.

hi,
A question, does the PIC hang up when the relay is switched when the lamp load is not connected.?

 

[kurrodu]

hi,
A question, does the PIC hang up when the relay is switched when the lamp load is not connected.?

No.

 

[Mr RB]

What's the point of the optocoupler when you use the same 5v supply to run the PIC and the relay???

 

[kurrodu]

What's the point of the optocoupler when you use the same 5v supply to run the PIC and the relay???

You are correct.

 

[ericgibbs]

You are correct.

You can buy ready made snubbers, 100R and 100nf cap in the same package.

These are normally placed close to the switching contacts to prevent arcing when switching inductive loads.

Its also a good idea to place a snubber close the inductive load.

The point to remember about switching incandescent lamps is that the filament resistance when the lamp is cold can be only 10% of the hot running tempr, so the inrush current can be high.

What types of snubbers have you tried.?

 

[kurrodu]

I have used MOC 3021 and a triac BT136 which solved the problem.

Will it be fine if I use inductive load? (since the circuit now is completely isolated)

 

[ericgibbs]

I have used MOC 3021 and a triac BT136 which solved the problem.

Will it be fine if I use inductive load? (since the circuit now is completely isolated)

hi,
The MOC3021 is a non ZC triac and you say the problem is fixed. OK

The inductive should be OK, I would fit a snubber device as suggested in my earlier post.

What is the inductive device. ?

 

[kurrodu]

hi,
The MOC3021 is a non ZC triac and you say the problem is fixed. OK

The inductive should be OK, I would fit a snubber device as suggested in my earlier post.

What is the inductive device. ?

Yes I have varied the inputs and triggered the output which has load connected (220Volts Ac and 40 Watt bulb)

I tried switching it on and off for 30 min continuously, the controller works fine.

The device that I will switch is a water purifier which has a small inbuilt pump.
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