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.
One thing i was thinking of was a mute wire on a parrot bluetooth kit...i believe its 3v when its telling the "radio' to mute and a ground otherwise.
thinking, believing or known?
does it mean you want mute the radio with this signal?
do you know which signal needs the radio for mute mode?
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?
i think you don't need a relay. this should work with few ampere. so you can use a transistor.
may be you can connect the signal directly to com-port. but i don't know it.
I was thinking transistor a while back.ill keep looking into it.
An whilst pennies drop, the harryberlin's relay problem is solved with the usual spike protection diode (1N4007 or 1N4004).
yes you're right, you can fix the problem with a diode.
but i think the better way is to use transistors.
or may be a small reed relay. but not such a big thing.
Transistors are not a better way to prevent relay spikes - ie, quenching the spike.
I don't see what relevance a dc-dc or dc-ac converter has - we are not 'converting' the low voltage output.
If talking about a transistor for a buffer for the relay coil etc you'd probably use an NPN transistor as on Open Collector output which could ground a 12V relay, or the load direct (if a few Amps), or control a MOSFET or other transistors.
I still don't see what relevance it has here - we are not 'converting' voltages nor providing a power supply/voltage. And the OP should have the call if bantering is welcome.
camo.b's 1.8V or higher output voltage turns on a transistor. That transistor can ground a relay coil, or another transistor. The output else its transistor could also control a MOSFET that can switch loads up to 50A and higher ($2, 100A).
Not that the OP Champak has yet specified a minimum voltage, but I suspect it'll be above 1.8V - maybe 3.6V etc.
If switching a relay coil, a reverse biased diode (1N4004 or 1N4007) can be placed across the transistor's Collector & GND, or as is often done, across the relay's 86 & 85 where 85 is the more -v, ie, GND. The Cathode/line end of the 1N4004 or 4007 diode goes towards the more +ve ie, Collector or relay 86. IOW the NON-line end to the transistor's Emitter or relay 85 which should both be GND in this case.
A 1N4004/4007 diode is the most common solution for relay coil 'self induction', ie the huge -ve voltage spike released by a coil when switched off. (Place your fingers across a non-spike protected relay coil when de-energisied if you don't believe me.)
The diode spike-suppression solution is ironically the cheapest as well as the best implementation (for common relay applications and electronics).