Maker Pro
Maker Pro

12V relay with 9v battery_not working

veeru

Aug 12, 2016
4
Joined
Aug 12, 2016
Messages
4
Hello all,

I am working on a relay circuit whose schematic is attached for your reference.
All the parts are of specification except the relay. I am using a 12V relay instead of 9v relay.

When powered on....
In the relaxed state the LED on the far left glows. When I press the button I hear a "tick tick" sound but the second LED does not glow. I even used a multimeter but found no continuity when button is pressed.

I dont know if 9v is causing enough force to switch the circuit. I still wonder where the "tick" sound came from.

Please suggest me if I should use a 12V? Is there anything I can do to switch with 9v battery?

Thanks,
Veeru
 

Attachments

  • relay_circuit.png
    relay_circuit.png
    74.6 KB · Views: 379

poor mystic

Apr 8, 2011
1,074
Joined
Apr 8, 2011
Messages
1,074
:) Hi and hope y're happy
The tick sound is made when a metallic switch moves inside the "relay" block.
When you press your button, electric current flows through a coil, which makes a magnetic field around the relay (which you could detect with a compass). The magnetic field causes a metallic switch to change position, which makes the sound.
Did the second led spring into life yet? There's nothing obvious wrong with the arrangement you posted. I think you are about to get your first object lesson in electronic repairs, and what it will probably hint to you is that most faults in electronic equipment occur where one thing is joined to another. Connectors, joinings, soldering and splicings are all likely sources of faults.
Have fun!
 

Minder

Apr 24, 2015
3,484
Joined
Apr 24, 2015
Messages
3,484
Do you have a 6v relay? if so you could use a couple of rectifiers in series with the coil.
Relays have what is known as a fairly large hysteresis a DC relay once it is pulled in will stay retained with much lower voltage, but first you need to energize it closed.which as higher than the minimum retaining voltage.
It sounds like your version does not like 9v!
M.
 

BobK

Jan 5, 2010
7,682
Joined
Jan 5, 2010
Messages
7,682
Why would you expect a 12V relay to operate on 9V? There is a reason that it is a 12V relay.

Bob
 

hevans1944

Hop - AC8NS
Jun 21, 2012
4,891
Joined
Jun 21, 2012
Messages
4,891
Please suggest me if I should use a 12V? Is there anything I can do to switch with 9v battery?
Yes, use 12 V battery. Just connect eight AA or AAA dry cells in series-aiding. Pay attention to polarity! Positive of one cell connects to negative of next cell, daisy-chained until all eight cells are connected together and you have one positive and one negative lead attached to the first and last cell in the chain. Relay should operate properly from this arrangement, and the extra voltage won't harm the LEDs with the 470 Ω resistor limiting the current.

If you want to switch with a 9 V battery, use a relay with a 9 V coil, as @BobK implied in post #4.

You can make any voltage you want by connecting dry cells in series, but I recommend limiting the number of cells to some number a lot less than one hundred cells (150 V) for reasons of safety. A lot of cells in series can deliver a powerful and dangerous shock!

You can also easily increase voltage (18 V, 24 V, 36 V ... etc.) by connecting 9 V batteries in series, easy because all you have to do is mate up the snap connectors, daisy-chaining the batteries. Again, don't try this with more than a few 9 V batteries because of the electrical shock hazard. If you take your 9 V battery apart you will find six individual dry cells inside, each about the size of the stubby pencil some people use to write down their golf scores. Look carefully and you will see the cells were connected in series, typically with little metal foils.
 

CDRIVE

Hauling 10' pipe on a Trek Shift3
May 8, 2012
4,960
Joined
May 8, 2012
Messages
4,960
You can also use a 12V wall wart. Most of us have massive collections of these things. Whatever you do DON'T be tempted to use an automobile or motorcycle battery. They are unforgiving if you make a mistake and can deliver enough current to weld a 3/4" drive socket wrench!

Chris
 

CDRIVE

Hauling 10' pipe on a Trek Shift3
May 8, 2012
4,960
Joined
May 8, 2012
Messages
4,960
You may also want to add a kickback diode (1N4002) as shown. It will increase the longevity of your switch.

Chris
upload_2016-8-30_11-37-58.png
 

veeru

Aug 12, 2016
4
Joined
Aug 12, 2016
Messages
4
Hi,
The 9v relay was not easy to buy. So I used a 12v relay.
I will use a 6v or 5v relay with my 9v battery to see if my circuit works.

Thanks for your answers.
 

CDRIVE

Hauling 10' pipe on a Trek Shift3
May 8, 2012
4,960
Joined
May 8, 2012
Messages
4,960
Hi,
The 9v relay was not easy to buy. So I used a 12v relay.
I will use a 6v or 5v relay with my 9v battery to see if my circuit works.

Thanks for your answers.
You can do that but will require an additional series resistor who's value must be calculated using Ohms Law. Do you know how to do it?

Chris
 
Top