To clarify the question I draw the following illustration:
Inside an enclosure I basically need a control such that when the SW switch above is closed, the mains relay latches if the momentary push button PB is pressed and released. And the mains relay stays latched unless the SW is opened.
Both relays above are normally open non-latching type. And as you see, I use a DC relay to achieve this. If SW is closed and PB is pressed and released, both relays will stay activated since the output of the DC relay is fed back to both relay trigger inputs. So after PB is released the Bulb will remain ON and can be turned off only by opening the SW.
So the operation required is:
SW is closed & PB is pressed and released --> Bulb is ON (unless SW is opened again)
SW is open --> Bulb is always OFF
My questions are:
1-) Is there a type of relay where one can achieve this operation with a single relay?
2-) What IC gate type would replace the Relay_DC?