I need to design a circuit to switch on a warning lamp or sound a hooter when a door is opened and the reed switch is activated by the magnet. I have herewith attached the circuit diagram of the test setup. My problem is that the reed switch fails within a few (3 or 4) operations though the current measured is in very small units.
Kindly advise me how to go about it to solve the problem.
The current threough the reed switch will be well over 100mA and will almost certainly also have a surge current as it closes. This will probably be tens if not hundreds of times greater than the reed switch capacity.
I would suggest you use a Triac to switch the current and use the reed to fire the Triac.