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Relay - most basic coil relay to show operation

R.William

New Member
Hi, I'm looking for the most basic 4 pin relay that can be powered off a battery 9v at max

this is for a project to show in most basic terms a relay working, so the coil can be seen etc, ideally I would like to power it from AA batteries - this is the most basic project etc

please could someone recommend such a relay - we use to have these at school when I was a kid but I can't find them anywhere.
 

Visitor

Active Member
One option, which probably isn't exactly what you're thinking...

A reed relay of the type Radio Shack (still, on-line) sells is a magnetic reed switch surrounded by a coil of wire. The reed switch can actually be removed from the coil without damage to either – I've bought these when I needed a reed switch.

Using a bare reed switch, you can demonstrate how bringing a magnet close will make the switch close. Then explain that the coil creates a magnetic field to do the same thing.

SmartSelect_20200803-092337_Firefox_copy_810x1255.jpg

Screenshot_20200803-092652_Firefox_copy_810x1267.jpg
 

Diver300

Well-Known Member
Most Helpful Member
How about a 12 V automotive relay? They are cheap. You can probably pick them up for pennies at a car scrap heap. You can take the cover off easily to show the contact moving inside. They will all work from 9 V.
 

R.William

New Member
Thanks for your Replies a Reed Relay looks interesting its worth thinking about.

Yes those automotive relays are exactly the kind of thing I want
I've seen some 6v ones like this
do you think this would operate with 4 AA batteries?
Does it need 40A to operate of it can switch a maximum of 40A?
 

R.William

New Member
ok it might be worth a try and I just saw some 5v coil relays if you or anyone else can recommend any please let me know, Thanks
 

gophert

Well-Known Member
Most Helpful Member
With a sharp razor knife, you should be able to trim the plastic case off of a 5v relay in a few minutes. Buy a few extras in case you clip an internal wire.
 

KMoffett

Well-Known Member
Are you trying to show the mechanical operation or the electrical operation, or both? Reed and automotive relays have the mechanism hidden. As gophert said, you might be able to cut the case of of a automotive relay. I did see some automotive relays with clear cases, that were SPST (4 pin) contacts:
Automotive relays
If you need to purchase them...where are you in the world?
 

gophert

Well-Known Member
Most Helpful Member
I did see some automotive relays with clear
Right, The old "crystal cube"/"ice cube" relays looked great.

Like theses...
 

eTech

Active Member
Hi, I'm looking for the most basic 4 pin relay that can be powered off a battery 9v at max

this is for a project to show in most basic terms a relay working, so the coil can be seen etc, ideally I would like to power it from AA batteries - this is the most basic project etc

please could someone recommend such a relay - we use to have these at school when I was a kid but I can't find them anywhere.
you might want to look at general purpose relays from Omron. They are about 1.5 inches tall and you can see the coil and armature operate thru clear plastic cover. The cover can be removed if you want. They come in various operating voltages.


 

R.William

New Member
Hi, I'm in the Uk
I've ordered a Learning Toy Relay from Ebay don't know if it will be any use, suppose to work at 3v

I Guess I could make one solenoid etc but its not really what I want

Yeas the Omron and some of those other IceCube ones look good

I don't know anything about 12v supplys, ill probably have to start another thread about that.

I might have some more questions and replies this is just more a Thnanks! and acknowledgement for the replies.
 

gary350

Well-Known Member
Get a free TV or free microwave on craigslist they have PC board relays inside with COILS. Relays with "COILS." Snap off the plastic case you can see the COIL. I have several with 6 volt COILS that I found in TVs.

 
Last edited:

Nigel Goodwin

Super Moderator
Most Helpful Member
Get a free TV or free microwave on craigslist they have PC board relays inside with COILS. Relays with "COILS." Snap off the plastic case you can see the COIL. I have several with 6 volt COILS that I found in TVs.

Microwave ovens , yes - plenty of relays.

But not very many TV's used relays - a few very old CRT ones used them for standby - but not many, and not for very long (it's a crude and expensive solution to the issue of standby).
 

KMoffett

Well-Known Member
R. William,
You never relly stated the purpose of the relay. Is this for a class project?
 

R.William

New Member
R. William,
You never relly stated the purpose of the relay. Is this for a class project?
It is a teaching and learning project at the same time ;), I remember very basic ones at school that worked from AA batteries but could not find anything similar.
 

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