Whats the difference between a resisted relay to a non-resisted relay! Cheers.
ct9a,
Jan 19, 3:59am
your question answers it
20498,
Jan 19, 4:01am
Ok. but what does the resistor do!
twaymouth,
Jan 19, 4:04am
Some indicator flasher units have a ballast resistor in them, and are also a relay hence the term resisted relay. Hopefully this is what you are after otherwise I am sure someone else will offer a better explanation
20498,
Jan 19, 4:09am
So to install a EFI relay would it have to be resisted!
twaymouth,
Jan 19, 4:17am
As long as it is a 12 volt relay on a 12 volt system you shouldn't need any resistors, I may however be wrong I am sure an EFI expert or automotive electrician can shed some more light on it.
jono2912,
Jan 19, 4:28am
Resist.
bigfatmat1,
Jan 19, 4:52am
because when you apply current to a coil it creates a magnetic field. when this is switched off the magnetic field collapses it creates a momentrey high voltage spike the resistor stops this. or a diode backwards. the voltage spike can damage sensitive electronics so it reccommended to use with electronic circuits
back emf is what it is called It can be a very high voltage and it is reverse polarity In my field commonly diodes are used to clamp this voltage because the diode is connected in reverse bias position the reversing polarity back emfflows through the diode and back through the coil which is dissipated .
de-spiking resisterscan usedhence the term resisted relay they are not as effective as a diode but more robust Iguess you would find both examples in a vehicle
High back emf flowing back into sensitive electronic circuitscan destroy transistors and cmos circuits etc found in most electronics .
High back emf has it's advantages ,one type of scada equipment I work on if it is depowered from the station supply which is 13.8 volts it wont restart till it see's 15 volts input so i use an old relay and touch it across the input ,the back emfwill momentary push the voltage high turning the scada unitsregulator on allowing it to start one useful purpose
jakeemon,
Mar 19, 3:07pm
If its a diode it will be there to protect the contact points from back EMF arcing.
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