Interface reed switch

[Darpan]

i have connected the two terminals of the reed switch directly to vcc and ground. 5volts supply is provided.
when i move a magnet near it….the terminals get short which is correct
but when i remove the magnet, the terminals does not open ,,,they remain short…
after solving thes problem, i have to interface it to 89c51..
 

[AJISH ALFRED]

Hi Darpan,

Since you’ve connceted the reed switch directly across the supply voltage, when it closes a huge amount of current flow occurs through the switch, which will make it permanently closed.

Use a resistor not less than 1K resistor in series with the Reed switch always.

[Darpan]

Thanks a lot sir,

I connected a resistor of 10k in series and now the reed is working fine..
Thanks for the help.

[AJISH ALFRED]

You are welcome Darpan. Please feel free to post your technical quieries any time.

[Author]

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