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Connect two products

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New Member
Hello All,

I am new to electronics and I am trying to connect two electronics products so that when one product is triggered another product is turned on.

I have a small reed switch alarm, with its own power, and when this is triggered i.e. a door is opened I would like it to turn on a small radio, which also has its own power. I figured that if I break the circuit on the radio at the on/off button and connect two extra wires from the speaker of the alarm to the radio on/off circuit so when the alarm is triggered then the radio will be turned on. But this has not worked.

So does anyone know if there is a general rule where I need to match the radio on/off circuit amp, volt, etc? And if so what components do I add to the wires coming form the alarm speaker?

Thank you.


Super Moderator
Most Helpful Member
It is impossible to give a definite answer without knowing the detail of the alarm unit.
Just connecting the "speaker" of the alarm to the radio on/off switch is most unlikley to work.

To me the most obvious way to do this would be to use a relay between the alarm and the radio.
Connect the relay contacts to the radio battery circuit OK, but where to connect the relay coil in tha alarm is anybodies guess with out detailed information about the alarm.

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