Reed relay smaller alternative

Hi guys

I'm working on a car project and I'm limited to space. I would like to know if there is any smaller alternative for Reed relay such octocoupler or any thing else which can handle 0.5A and at the same time has three output such relay with 5 pins (NO, NC)


FETs would be the obvious one, but you need to explain what it is you want to do.

FETs would not do the job as they have only 3 terminals I need something with 5 terminals (2 for energize the coil and 3 for connecting load)
I'm just trying to connecting some wires to each other but they won't draw more than 0.5@max.

For your purpose, a fet has one terminal. But you can use multiple fets connected to one or more pins on an Arduino.

Draw a full schematic with the reed relays so we can see how it works or how you think that it would work. Photo of pencil drawing will do.

And another important question: how small is small enough?

Reed relays are about the smallest relays alongside signal relays, no opto coupler can handle anything like 0.5A.

Its not clear if you require galvanic isolation - in which case a signal relay is the choice to go for. If isolation isn't required MOSFETs could be used but you need to understand exactly what is being switched in that case.

It is a clear XY problem.

it seems he is angling for a SPDT function, but not telling why. :astonished:

You can get very small reed relays about 5mm in length but they won’t handle half an amp.

Here's a bunch of reed relays that can handle 500mA

@CrossRoads' link:

Exactly how small do you need the relay to be?

There are lots of SPDT "signal relays" in the 10x15mm or smaller size.

There are relays in TO-5 cases, but they're most aimed at military gear and you'll get sticker shock...