Making two first circuits

[alaios]

Dear all,
I am very very new to this world. I am currently trying to implement a small project.

-I would like to have some help with relay circuits. I have a 3 Vdc current that I want to use to open/close a 12volt circuit that gives energy to a electrical pump. I have tried on internet to buy that ready but I have failed finding out one(i have searched on farnell web site). I do not understand the parts I will have to look for.

-The second think is that I would like to learn how I can downgrade the voltage I get from a source. How I can convert a 6voltage for example to a 4voltage? How the circuit would look like and how each component would be called so to proceed and order them?

I would like to thank you in advance for your reply

Regards
A

 

[OLIVE2222]

Hi Alaios and welcome to this forum !

-For the relay you need one with a 3Volts DC coil

Here a Farnell filtered result accordingly:

http://be.farnell.com/jsp/search/br...arametricAttributeId=&prevNValues=2002+202502


-For the voltage "downgrade" you need a voltage regulator. google for LM317 a popular adjustable regulator.

Olivier

 

[alaios]

Hi I appreciate your immediate response.

If I understand it right, the manufacturer to give you flexibility
they made relays that can be controlled with 3 volts and support a range of voltages for the circuit they control.

So for example this one here.
http://www.farnell.com/datasheets/612075.pdf
is bothering me with the terminology.

There are two Voltages I want to differentiate. The first one is the voltage I have to apply to activate or deactivate the second circuit (that I want to be 3 volts) and the second one should be the voltage the controlled circuit needs (in my case a 12 volt air pump).

Now back to the pdf I just gave the link:

see on page 1 the table at the bottom.... I can not really map what I described above in the table there.

Could you please help me reduce this gap?

I would like to thank you in advance for your reply

Regards
Alex

 

[OLIVE2222]

Yes the manufacturer give you the flexibility

For your example, and for any relay, you have 2 data set:

-The coil data, here a small DC voltage needed to drive the coil

=your " voltage I have to apply to activate or deactivate the second circuit"

-The contact data ,an higher AC/DC voltage and higher current (comparable to a switch specs)

=your " voltage the controlled circuit needs"


Hope that the gap is reduced now!

Olivier

 

[duke37]

The relay contacts will need to have a specification exceeding 12V and exceeding the current that the pump draws.

 

[alaios]

Hi and thanks all for the answers. I will read all the answers carefully later and I will come with feedback

Alex