How to arrest the spikes in the micro controller circuit.?

[narithota]

Hi

Iam switching ON-OFF the relay using 89C51.Relay is connected to the 230 V contactor.

While doing this operation some times contactor generating the spikes

Due to this spikes my circuit getting reset.

How to arrest the spikes in the micro controller circuit.

Please provide design considerations and precautions while designing micro controller circuits with high voltage.

Regards
nari

 

[tvincent]

Re: spikes

Place a diode accross the relay coil. Cathode side goes on the positive. Make syre the diode voltage can handle the peak spikes.

 

[ashad]

Re: spikes

hi,

Same problem i was facing with same 89C51, then my prof suggest me use Snubber circuit

connect the 0.1UF (400V) & 100R(2W) in series b/w the NO & common Contact of the contractor

 

[narithota]

spikes

Thanks for suggestions

Can you tell what is application of the Snubber circuit? How it well work in the my

circuit.

Iam using diode across the relay coil also.

Here we contacted contactor to the relay. This contactor is working as switch.

When it is suddenly ON or OFF at that time it is drawing more current at that

instant of time.

At that time supply Vcc (5v) fluctuating due to the sudden current variations and

it is reseting the circuit.

Regards

nari

 

[ashad]

Re: spikes

Snubber is used to reduce the voltage spikes, as i told u connect this circuit with common and normally open contact of the relay or contractor

as shown the above fig

C=0.1Uf (400V) R=100ohm 2Watt