pebe wrote:I note the data sheet specifies a tantalum (in preference to an aluminium electrolytic). I normally use the tantalum bead type because it’s compact.
I've read through the data sheet and other articles but the more I read, the more I seem to get that for my simple circuit there are limitless possibilities for cap selection. For example, for C3, a 100µF aluminum cap will suffice though a tantalum is preferred. However, if a tantalum is used, the value may be lowered to 47µF (even lower for other considerations). For C1 and C2, the consensus seems to be aluminum for cost considerations. Would there be any compelling reason to use ceramic for either C1 or C2?
pebe wrote:Switching off would then leave the field open-circuit and the energy left in it by its magnetic field would dissipate as an arc at the relay contacts and possibly destroy them. Adding a reverse biased diode across the contacts as a suppressor would prevent that.
Added, thanks.