Ron wrote:
>
> I use thes types of relays for many things.
> If you have the ones that actuate from 3 to 32 volts , it would be easy to
> get some
> interferenc from RF dropping the actuating voltage below 3 volts if you are
> running
> it at 5 volts. The input circuit is opto -isolated so you are running an LED
> to
> fire a triac.
This one is rated 3-8v, although it said in the All Electronics catalog that it
'works on 12 volts'. However, I felt that it would be best to stay within the
rating.
> Some of these devices wait for a zero crossing of the line to switch.
> If you get interference at a zero crossing spot , the triac would wait for
> the next
> crossing and you would miss a half cycle......this might be enough to surge
> the
> relay on the next half cycle.
>
> I would suggest raising the actuating voltage so that you have a larger noise
> margin or place a reasonably large cap across the input to let it run the
> diode
> for a few cycles should interference drop the actuating signal below 3 volts.
I certainly can put a capacitor across the input. However, the input is quite
well-filtered for RF, having a pi-section filter at the relay. Interestingly,
the filter did not seem to have any effect. What did help was bypassing the ac
line. I'm not sure I understand why this is so.
Vic K2VCO
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