Hi everyone

I need to make a circuit with the following elements:

The output will be a siren connected to a 230 V and 50 Hz network. The control circuit will use a 9 V battery as power supply and an operational amplifier must be used, the siren will be activated with a relay. The alarm will be activated when the temperature is higher than 60 degrees Celsius.
Now this what I have,I think the mistake is in the output but I don’t know how to fix it. (I used simulide for the simulation)
Thank you

 

Hi Mer,
Try this for the relay connection.
E
Update:
Check the polarity of the PTC.!!

 

Hi Mer,
Try this for the relay connection.
E
Update:
Check the polarity of the PTC.!!

I Don’t get the line in the photo you attached where does it connect??

 

hi,
Line, Is the Mains supply 'Hot' wire at 230Vac and N is the Mains Neutral wire.

OK.?
E
Translated:
Line y N es el suministro eléctrico de red de 230 V CA para la sirena.

 

Hi, I tried something, but the output seems to be the problem,the relay doesn't close so the current doesn't pass and does not activate the siren, I think my input and control circuit are correct.

 

hi,
Line, Is the Mains supply 'Hot' wire at 230Vac and N is the Mains Neutral wire.

OK.?
E
Translated:
Line y N es el suministro eléctrico de red de 230 V CA para la sirena.

Hi, I tried something, but the output seems to be the problem,the relay doesn't close so the current doesn't pass and does not activate the siren, I think my input and control circuit are correct.

 

Hi Mer,
Look at the way in my diagram I have drawn the relay circuit, yours is wrong.
E

 

Hi Mer,
Look at the way in my diagram I have drawn the relay circuit, yours is wrong.
E
View attachment 284518

Could you elaborate?

 

hi,
Your circuit modified.
E

Note:
Your first circuit was using a PNP transistor, your latest circuit is using a NPN transistor.
The 230Vac Mains must NOT be connected to the circuits 9V ground rail.!!!!

 

,

 

hi,
Your circuit modified.
E

Note:
Your first circuit was using a PNP transistor, your latest circuit is using a NPN transistor.
The 230Vac Mains must NOT be connected to the circuits 9V ground rail.!!!!


View attachment 284521

Hi,So I made the modifications and tried also another circuit, because the BJT had no effect on my circuit.

 

hi Mer,
Where is the current return path for the Siren supply?
Also, the OPA's will NOT work.

What course are you studying.?

E

 

I'm taking a mandatory course of electronics, I actually study multimedia so it's not electronic engineering, I'm pretty bad at it.

 

hi Mer,
OK,
So decide which circuit you want to study and use, and I will modify it to suit.
E

 

This one

 

hi Mer,
You cannot drive a relay coil with a normal OPA, the OPA cannot output enough current for the relay coil, you need a driving transistor.

Choose the PNP or the NPN circuit.

E

 

hi Mer,
You cannot drive a relay coil with a normal OPA, the OPA cannot output enough current for the relay coil, you need a driving transistor.

Choose the PNP or the NPN circuit.

E

 

hi Mer,
Check this out.
Uses a 9Vdc relay
E