Hi All,

I had designed a circuit and it worked fine in the lab but it failed miserably in the field. This circuit controls a few relays which switch ON/OFF motors, without the motors the circuit works fine but when the motors are connected the uC(AT89S52) hangs and gets heated up and we need to restart the machine. Now we have come to the following conclusion

1>Use a spike buster
2>Use watch Dog timer
3>If even then it doesn’t work use a UPS…

I don’t think that we will be able to use the third option…
So please share some techniques to avoid this noise…


Rgds
Raj