It not the voltage that triggers its the mA. I think if you have a lower voltage you need to use a relay for that voltage and then use that relay to trigger the 12v relay. Like a 5v relay that triggers a 12v relay. Hope this helps SNO
Implicit in Sno's reply is that you match the relay's nominal or rated coil voltage to the voltage you are using - eg, 12V if 12V, 5V if 5V, and any voltage if an Open Collector aka GND signal.
IOW you do not use 5V to turn on a 12V relay because - even if it does - it will not have its full contact force and hence be prone to (1) fire or (2) open circuits on bumps or if hot etc.
What is a good way to operate a 12v relay from a lesser voltage source...say 1.8v,3vor 5v is the a common tidy way to do this?....ive often thought of this.
Thru a buffer...
Usually Open Collector - ie, they turn on a device (transistor, FET etc) that connects the output to 0V aka GND. As long as it can handle the relay's coil current (say up to 250mA for typical automotive 30A relays) then it can turn on any voltage relay. (As before, output to relay coil 85 and other end 86 to whatever +V it uses.)
Whatever output (1.8V etc) must be able to turn on a transistor etc.
self induction happens when you cut the steering power from relay.
the magnetic field falls down and induct a voltage back to steering part.
can destroy yICs, if you don't terminate this selt induction.
thats why the question where do you get this low voltage.
I know the parrot outputs a +3v when muting a sterio..i want to use this as a input for a mjs usb in/out or a joycon...either way i want the carpc to pause the current media when i recieve a phone call.however its done i need a alt-D (keystroke)to be issued upon 3v from the parrot...just need to be able to operate a relay from that voltage. Any thoughts?