Why not use relays in place of a fet job?

viperdout · Post by **viperdout** » Tue Feb 22, 2005 6:35 pm

Well, I've seen 5 volt relays used on xmods, and even though they get rid of the propo function, what would it matter on a Bit/ZZ, except for the SE? It's supposedly more efficent, so I don't see why not, and it'd be really easy to solder on. Anyone have a reason to say nay so long as the realy trips at a low enough voltage for a ZZ/Bit? To me, it seems like the perfect solution to replacing the fets on the board.

betty.k · Post by **betty.k** » Wed Feb 23, 2005 5:45 am

have you seen the size of a relay?

Matic · Post by **Matic** » Wed Feb 23, 2005 9:48 am

That would be waste of time.... Fets have VERY little inner impedance, which can be ignored, plus you can`t make dual speed with relays.

viperdout · Post by **viperdout** » Wed Feb 23, 2005 11:30 am

Betty, I've seen some pretty small relays, and I think if there's a relay that turns on at a low enough voltage, it could be fit in. Hall, I found a low-voltage indicator for my MT that's small enough to fit in the Camaro body's rear window! At least answer me this: would it work in theory?

betty.k · Post by **betty.k** » Wed Feb 23, 2005 4:33 pm

of course it would work, but it's old technology. a fet is far superior to a relay in this application.

viperdout · Post by **viperdout** » Wed Feb 23, 2005 4:43 pm

betty.k wrote:of course it would work, but it's old technology. a fet is far superior to a relay in this application.

That's what I wanted to know. Thanks for the info.

ph2t · Post by **ph2t** » Thu Feb 24, 2005 6:28 am

the thing is viper is that the coil in the relay would prolly suck more current than the motor it's powering, especially in a 1/64 application...

ph2t.

viperdout · Post by **viperdout** » Thu Feb 24, 2005 9:02 am

ph2t wrote:the thing is viper is that the coil in the relay would prolly suck more current than the motor it's powering, especially in a 1/64 application...

ph2t.

Yes, but isn't that coil powered by the motor, while the motor is drawing from the battery? I thought that the electromagnet in the relay closed when the PCB applied voltage, then the current flowing through was drawn from the battery itself, but I'm not nearly as good as you electronics guys. I figured it's worth a shot.