Introduction: Relay

About: in Electrical Engineering. Microcontrollers,PLC specialist programmer and embedded system developer.

Merry Christmas! I believe many of us know what a relay is. I have a small relay at home. I bought it few years back, I know how to use it, but I never actually tried to make (assemble) one myself until 3 days ago and after some trial and error I was able to get my solution. So this instructable is not only on how to use an already assembled relay module but also on how to assemble yours as well using a breadboard or printed circuit board (PCB).

Step 1: Part Selection

1. Relay
2. Breadboard
3. LED
4. Diode
5. Two Resistors ( recommended 1k ohm and 220 ohm).
6. NPN transistor ( recommended BC639).

Step 2: Connection.

I don't think I have to say much about the connection. since the image shows everything. usually when browse google the connection is not setup in this manner. The images I saw on Google made it wee bit difficult for me to understand. That is why I am setting up my diagram this way for those who think like me.I hope this can help anyone looking to setup a relay module. Thank you until next time. Bye.

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    4 years ago

    I do not mean to be... negative, I guess... and I hope this doesn't come off as such.

    I notice in your bio that you have a in Electrical Engineering so I would assume that you already know this, but I wanted to elaborate for those who might not.

    A couple of times, you mentioned "building a relay." That is misleading for those with little to no basic electronic knowledge. What you are describing here is not how to build a relay but rather how to build a relay control module. To actually build a relay (which I did as a kid beck before the world of electronics became plug-and-play as opposed to truly building your own circuits) would require winding a coil on an iron core and fashioning a set of contacts with a spring return.

    One more small thing. In your diagram, you need to add a dot to the connection where the anode of the diode, the collector of the transistor and the coil tie together. Without that, it could mean that the diode and the transistor are connected without the coil being also tied to that same point. Finally, the transistor needs the arrow added to the emitter to show which is emitter and which is collector as well as whether the transistor is an NPN or a PNP.

    Like I said, I'm sure you already know all of this, but sometimes it's easy to overlook something assuming that everyone must know it. Instructable readers are not all electronics technicians/engineers so even seemingly basic information needs to be added to help aid those looking to learn the craft :)

    Rock Michael
    Rock Michael

    Reply 4 years ago

    I have to admit I overlooked these things. I made that diagram with
    paint , and adding such little details can be a pain.But, I guess I
    should add them. updated . :)