Radio Shack 5vdc spdt mini relay
we2r1two008
Posts: 16
I am trying to turn this relay on and off with no success. I have the bs2 boe. I am using a transistor npn type. Checking the transistor, it is working fine but the relay is not turning on and off. Can someone explain in laymens terms how to set this up?
Comments
Use an ohm meter to find the coil pins. (if you don't know how, ask)
Check with an ohm meter the Normally closed pins and the normally open pins. Now you have a basis to test the device.
Apply 5V to the coil
Check with the ohm meter that the normally open pins close and the normally closed pins open when you apply 5V
If the device is working then you may have found the following by this excercise.
1. you miswired the device
2. your transistor is not working or you have it connected wrong.
Of course , you need to supply a drawing of your circuit for anyone to help if it's number 2 above.
It could be you don't have enough current through the coil, it could be you don't have enough current on the transistors base.
I think I covered all the possibilities, the point here is to inspect each point of the circuit and independently test the components involved in the circuit.
So you don't have to have a datasheet for the device if you use a meter to find the correct pins to connect your circuit.
·
Is it the relay in this picture?
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Think Inside the box first and if that doesn't work..
Re-arrange what's inside the box then...
Think outside the BOX!
rsk.imageg.net/graphics/product_images/pRS1C-2160389w345.jpg
www.radioshack.com/product/index.jsp?productId=2062480#tabsetBasic
I appreciate you guys taking the time to help me out.
Also, 90 mA is quite a lot of current for a 9-volt, which I usually expect to be limited to about 50 mA max.
Post Edited (allanlane5) : 4/29/2010 12:34:14 PM GMT
Hey, nobody's going to die; hopefully nobody will feel attacked.
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Think Inside the box first and if that doesn't work..
Re-arrange what's inside the box then...
Think outside the BOX!
[noparse][[/noparse]Maybe they noted that stuff on the back of the packaging?· RS didn't present that on the webpage.]
So, anyway, it specs a "55 ohm" coil.· That's a lead there.· The thing to do is to find/identify the coil pins.· You need to get an ohmmeter and find the two pins where you get 50 ohms or so of resistance (all the others will·yield·either·shorts or opens.)· It's process of elimination, there are only 5 pins.· Get in there and dig.
Do that and more help will be made available.
Post Edit -- Somebody here Deleted his post, I note.
Either way, he exceeded the rating of.... .090 amps.
If he left either one connected for more than a few seconds..(better odds w/9vdc)· I doubt he'll find a 55 ohm reading anymore. . . . . Too bad that coil's so small.... I do love the smell of smoke while I'm testing....(As long as I have spares.)
Just throw away those·plastic lumps (uh burnt relays)·&· get more!
Me, I would suggest next time you test the relay with a voltage less than the max rated. In my experience, any mechanical relay will trigger when presented with as little as 2/3 of it's rated voltage.
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Before you criticize someone, walk a mile in his shoes. That way if he gets angry, he'll be a mile away and barefoot. - unknown
Let's just wait for we2... (Le OP) to get back to us and go from there.
That said.. You could've used a·voltage regulator to bring the 24VDC down to 9vdc or 5vdc.
Hope this thread helped you!
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Before you criticize someone, walk a mile in his shoes. That way if he gets angry, he'll be a mile away and barefoot. - unknown
@PJ, Diplomacy is no a stranger to me... But I feel safe in my theory & I stand by it...the captain goes down with the ship!!
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Before you criticize someone, walk a mile in his shoes. That way if he gets angry, he'll be a mile away and barefoot. - unknown
I do appreciate the help and of course I am never satisfied so back the the other relays for another round.
Ok, there is a few more things I need help with. In a schematic that I didnt understand, I read a note about a diode being used to protect the controller from the coil. (I think) Could you give me a short answer to that so I dont fry this bs2. Another thing.. the relay I am using calls for 1050 omhs. I do not have any resistors in this setup. Is that bad?
Now I am not one to use transistors for switching on and off I typically use mosfets that do not require a resistor on the gate. Driving most transistors however I think require a resistor as they are current driven not voltage driven. It would be nice if you were to post a schematic or give specific part numbers you may get better answers.
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Think Inside the box first and if that doesn't work..
Re-arrange what's inside the box then...
Think outside the BOX!
I think it was in·the first reply after your originally post the 24V statement came. Metron9 then accidently blamed you for that statement in his second post.
To solve this mystery we need the 24V ghost to come back to the thread again.
Post Edited (Moskog) : 5/2/2010 8:54:00 AM GMT
A look at the facts. I post, then one reply.. then I give thanks for the "replies" being plural. Feeling a bit CIAish I dig in the history of google chrome and find the schematic that was linked in the deleted post.
http://www.kpsec.freeuk.com/projects/simplet.htm
Just for fun, who made the post?
Back to bussiness / pleasure. I am using the boe with this relay:
http://www.radioshack.com/product/index.jsp?productId=2062479
I have a NPN transistor wired to pin 1. GRD from another 9vdc is also attached to the collector and of course the extra 9vdc battery + is connected straight to the coil.
I have never made a schematic. I am sure that during this process, that will be next on my list of things to learn. As for now, what about a reply like "Hey.. Stop! Your gonna fry that BS2!" Or maybe, just a simple atta-boy. lol
Edit:
Ok, so the free version of PCB artist sucks. Can I get some suggestions regarding schematic creation software?
Post Edited (we2r1two008) : 5/2/2010 11:24:27 AM GMT
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MOORE'S LAW: The capabilities of electronics shall double every 18 months.
cloyd's corollary: Hardware is easy, software is hard.
Well, probably not your whole BS2, but maybe a pin. You are right above where you mention that you need a diode across the coil of the relay. When the magnetic field of the coil collapses, it creates a high voltage reverse spike. This can eat your drive transistor and possibly your Stamp pin. Just about any old diode will do. Connect it with the band pointed towards the + side of the relay coil, as close to the coil pins as you can.
Atta boy!
Jonathan
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www.madlabs.info - Home of the Hydrogen Fuel Cell Robot
Jonathan
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www.madlabs.info - Home of the Hydrogen Fuel Cell Robot
On the project. This schematic (attached below) depicts a microcontroller driving a relay.
If you post the transistors part number, or link to it's data sheet, as well as the voltage you are using and the specs of the relay (voltage and current) I am sure someone here can give you the calculations to perform to decide on the resistor value needed to drive the relay.
Here is the thing, the resistor creates a current source or x. The transistor then allows a current to flow that is x times the amount of current flowing into the base. Without a resistor to the base the current may be too large and the current could flow from the base to ground shorting the stamp pin to ground and making smoke.
So the voltage for the relay and the relays current need to be known as well as the voltage you plan on driving the relay with although, and i am not sure about this but another resistor could be used to drop the voltage to the relays coil, i.e. you have a 5V voil and you have 9v battery instead of connecting the battery directly to the coil you use a dropping resistor to limit the current through the relay. Again i must point out using the correct voltage is a better option.
Your mission here is to learn how to take all the part information specifications and use calculations to figure out what other parts, in this case a resistor to the base and of course the protection diode for the kickback of the coil. Remember there are many different diodes, some very small and some very big, with a protection diode you just need one that is big enough to take the current and voltage the coil will generate when the transistor is turned off.
So get the magnifying glass out and read the numbers on the transistor unless you have the warapper from RS that shows the part number. Google can find the datasheet that has it's specifications.
Check out this showing inductive kickback, Click on the little white line at the bottom of the circuit where the small capacitor is located. The switch opens up and the current flows back through the diode. Without the diode something will smoke.
http://www.falstad.com/circuit/e-inductkick-block.html
Here is an index to many circuits you can see on screen working. You can also make your own circuits using this free java program.
http://www.falstad.com/circuit/e-index.html
Main site to all applets http://www.falstad.com/mathphysics.html
look for Analog Circuit Simulator Applet on the linked page above. Below is the link.
the actual applet you need for viewing common circuits and making your own http://www.falstad.com/circuit/
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Think Inside the box first and if that doesn't work..
Re-arrange what's inside the box then...
Think outside the BOX!
Now i'm wonderin' if somone "faked" a quote?· (Is there a forum tribunal for the inqusition?)
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Before you criticize someone, walk a mile in his shoes. That way if he gets angry, he'll be a mile away and barefoot. - unknown
And just to think, I had let the past go and forgotten all about the mysterious post. (Well, maybe not totally forgotten.)
You have never been accused of pouring salt in an old wound or stiring the pot huh?
At this moment I realize two things. I am using the same terms as a elderly lady and I am looking at the word "stiring" wondering if it is spelled right.
To keep this post from totally being off subject I'll have to ask about another of lifes mysteries. Why does my 5vdc regulator read a steady 3vdc?
Again you might ask why does one of the components on a circuit board not work?
How the heck would anyone know if you do not provide the regulators part number and your wiring schematic, are you measuring with a load or without a load.
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Think Inside the box first and if that doesn't work..
Re-arrange what's inside the box then...
Think outside the BOX!
Maybe voltage regulators always deliver a little less than stated on the packaging.
I know as much about electronics as you know about walking a 4" iron beam with a 90lb
harness/belt, 200' in the air. lol I am trying.
The part is at the link below. It is check without a load.
http://www.radioshack.com/product/index.jsp?productId=2062599
Do you have 7.5V on the input and do you have the proper capacitors .33uf on the voltage input pin and .1uf on the output pin?
You should see 5V output with those parameters. If you are only giving it 5V then you will see 3 to 3.5V with no load typically.
Some better regulators are called LDO or low drop out regulators. They don't need so much overhead voltage. For example you want to use 4 D batteries at 6V and regulate to 5V you can't do it with a 7805 so you find a LDO regulator. If you are using 9V you should see 5VDC for sure.
I know enough about the iron beam 200' in the air NOT to even try it, I shake like mad for hours when I have to go up on my roof.
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Think Inside the box first and if that doesn't work..
Re-arrange what's inside the box then...
Think outside the BOX!
It makes sense now.. I appreciate it.
As I read some of the posts here and in other topics I an trying different compnents one at a time when possible to
see how they work. I am a little bit on the short-winded side when it comes to reading comprehention and committing
those things to memory.. I acutually have to do it and see it work to really understand. I tried using a capasitor to measure rc time and also to smooth out a dc signal. Both times it worked great. You have me stumped on the use of 2 coming from the battery.
Is there an article you can link me to or further explaination? Thanks.
If there's no heat....then it's most likely·1)failed.· or 2)NOT a 5vdc regulator!· (It's happened to me b4...wrong item packaged.)· Check the part number of it again to be sure......
And, as to an old wound.....(I was just solving a thought problem...I love logic problems.· Wasn't really trying to create another "issue" tho.)......Oooops.
·EDIT>> meton's comments are also good! ( I didn't see them yet...misssed that this thread went page2)
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Before you criticize someone, walk a mile in his shoes. That way if he gets angry, he'll be a mile away and barefoot. - unknown
I am not aware of most regulators having the ability to be connected in parallel at least not without additional circuitry.
http://electronicdesign.com/article/power/double-your-output-current-with-parallel-voltage-r-9270.aspx
A transistor pass circuit is usually used.
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Think Inside the box first and if that doesn't work..
Re-arrange what's inside the box then...
Think outside the BOX!