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Electronics => Beginners => Topic started by: redgear on July 14, 2020, 01:59:21 pm

Title: Which circuit choice is better?
Post by: redgear on July 14, 2020, 01:59:21 pm

I'm building a circuit to control to cut off supply to the load when a microswitch is released. I will be using microcontroller and a relay to control the power to load.

[attach=1]

In the above schematic I have wired it in such a way that, if the microswitch(SW23) is released, it is guaranteed that the supply to the load is cut-off even if the relay or the microcontroller fails. But the downside is that the microcontroller does not know the state of the switch, so the relays will be ON even if the switch is released in the middle of the operation.

The other way will be to connect the switch to microcontroller and let the microcontroller control the relays. But if the relay contacts are melted the circuit stays ON forever. Two relays in series can reduce the probability of this event or I can use a DPST relay so even if one pole is iced, the other still works.

I will be switching around 2.5A at max. Do I need a snubber network on the relays? What do you guys think is a better design?

Thanks