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Topic: Relay - increase intensity of a digital port (Read 2894 times) previous topic - next topic


Hello !
I use a relay which works with 100mA according to the datasheet but, in practice, I measured 130mA.
The relay : G2RK-1
Datasheet : http://doc.chipfind.ru/pdf/omron/g2rk1.pdf

First question : Is this relay work well with 230Vac ?

As you can see, it works with a double coil. Therefore, the schematic I'm trying to achieve is half of the full schematic.

I want to increase intensity of a digital port to use this relay. I found this :

But I don't have 2N2369. How to found an equivalent ? For example, I have a BC547, does it work ?

Thanks you !

PS: if I'm wrong in my reasoning, report it to me  :)


That circuit is OK, although R3 is not needed. BC547 is only rated at 100mA so not really suitable fro driving your relay. BC337 would be OK. Don't forget to connect a flyback diode in parallel with the relay coil.
Formal verification of safety-critical software, software development, and electronic design and prototyping. See http://www.eschertech.com. Please do not ask for unpaid help via PM, use the forum.


Q1: Look in the datasheet page 3 , under Rated Load,  I see at least 2A @ 250Vac   , so you can switch mains voltages (be carefull)

Q2:  many transistors for your type of usage (LED switch) will be fine ,  BC547 , 2N2222
- Make sure its a NPN
- A 100k resistor in the base is fine.
- Emittor connected to GND.

One note :  For switching the LED like in your schematics the BC547 is fine, It can handle the current of the LED,  
But if your want to switch a relay with this BC547 you have to watch out,  a (NON)-Latching relay coil requires more than 100mA  and the BC547 is only rated to 100mA.
It is unclear to me what the rated voltage of your relay is ,  when in doubt use a 2N2222  it can take 800mA,


Thanks for answer  :smiley-mr-green:

I remeasured the intensity. I found 106mA and 146mA (depending the direction). So BC547 is maybe to small, don't think so ?


I looked to a transistor which support 150mA and more but I didn't found.

Is it possible to use divers small transistors to add the current final ?

I found an other possibilities, use an optocoupleur.

I need some help to progress  ;) .


Where do you buy your electronics, ?,   I know in France there is a Conrad.fr ,  you could fill a shopping cart there.


Oh, I know that I can buy but if you could see all I have you would understand that I can do differently.

Besides, I just found this in my tiroire:

Is that one of the two could replace the 2N2222 ? (I'm french and I find hard to read datasheet...)


They can handle the current but they both have a very small gain, in the order of 25 or so.


I made it! Finally, I used a "BSX46 8605". If someone want a schematic, it is with pleasure that I would post.

Thanks all and see you !


Hello, I'm back for a last question.

I don't put any diode. If it useful, can you explain me how to put it on my system ? (don't forget that I have 2 coils). Thanks  XD


You put the diode reversed biased across each coil you are driving. That is with the anode to the positive end of the coil and cathode to the negative end.

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