Pic 16F887 resets when 2nd relay opens

[runman_up]

I have an application with a microcontroller activating two 5V relays through transistors - they activate fine from transformer/bridge rectifier regulated power no problem - I just get the problem when they turn off - after the second relay turns off it resets the pic chip! Do i need extra diode or something in there? The relays each have a protection diode on them.

Help

 

[Pommie]

Do you have decoupling capacitors? Can you post your schematic.

Mike.

 

[runman_up]

Yes - a 0.1 mf capacitor at the ground to positive at the pic - I have a smoothing capacitor before the regulator of 1000mf. Sorry schematics pretty poor currently so bear with me.- I am new to this - how do I post a picture from my hard drive?

 

[KeepItSimpleStupid]

use "Go advanced/Manage attachments". It may take a day or so to be able to post pics for new members.

 

[aljamri]

Hi runman,

your picture has to be somthing like .gpj or and put say on desktop, press Go Advanced button, scroll down and find 'Attachments Managments' where Browse for your picture and upload it.

thats it

 

[Wp100]

Hi,

Apart from a schematic, what load is the second relay switching ? - are you using any supressors ?

Also do you have any input switches on long wire leads or a reset switch on Mclre ?

 

[Mosaic]

A snubbing/freewheel diode rev. biased (1n4001) across the relay coil is essential!

 

[runman_up]

Supressors/MCLRE

Thanks!!!
I am using a reversed diode across the activating relay coil.

what load is the second relay switching ? probably 2 or 3A on the AC side - Using any supressors ? No - not sure what they are

Any input switches on long wire leads? Yes a foot long 22 ga- or a reset switch on Mclre ? No I did not seem to need it.