# Should I use relays or is there a better way

Please forgive the basic question, I'm a novice at electronics.

I want to have an Arduino connect two pins of another circuit. I've measured the volts going through the pins as around 4V and the amps at 13 microamps (i.e. 0.013mA). Everywhere I've looked that talks about having the Arduino connect two points on another circuit the answer has been to use a relay. But when I started looking up how to determine what type of relay I needed I found that every relay I could find seemed like overkill for what I'm trying to accomplish. So first off, I was wondering if a relay is really the best way to accomplish this or if I'm headed down the wrong path.

If a relay is the correct way to accomplish this, I wanted to know if these parts I've listed below make sense for the relay circuit. I started by finding the closest relay to what I thought I would need, and then using this instructable to try to give me a guideline for what I'd need for the other parts. But since I don't really know what I'm doing I might be way off target with these parts, so any guidance is welcome.

relay: 9007-05-00
transistor:KSD261CGTA
diode: 1N4007
resistor: 4k ohm

If you are not willing to tell us what you are trying to do, there is no way to offer advice. I guess you will just have to be like the rest of us and try it and if it makes smoke, try something else.

Paul

Stab in the dark.
That voltage and that current, you could use that reed relay.
A 5volt/10mA reed relay can be driven straight from an Arduino pin.
You still need a 1N4148.... kickback diode.
Leo..

13µA? Just connect it straight to the Arduino pin, so long as the two circuits can share a ground.

You maybe

MorganS:
13µA? Just connect it straight to the Arduino pin, so long as the two circuits can share a ground.

I think the OP is looking to connect two pins of another circuit together, so can't insert the arduino in between.

You could also use two mosfets to act as the switch. You can see a short piece I put together on it at Power circuit redesigned! | Discovering my makerself
(caveat: I tinker, and am not a pro, but it may be helpful for you)

If you need to connect two wires from something else together, and you can't have the Arduino share a ground with that other device, you need a relay (or, maybe, an opto isolator).

Any method used to complete that circuit will be overkill - it's low voltage at virtually no current. That's fine.

Thanks everyone. I really appreciate the help. This gives me some additional things to think about. I have some more research to do.

ksenter:
Thanks everyone. I really appreciate the help. This gives me some additional things to think about. I have some more research to do.

If there is no need to keep the grounds separate you can use a transistor with a current-limiting resistor.
If you need the grounds to be separate, just use an optocoupler with a current-limiting resistor.

It might be a good idea to make sure you meassured the current correctly though.