Gas leakage circuit

Thread Starter

abdujellah

Joined Apr 24, 2016
5
Hello
i want to ask about the circuit attached .
1- what transistor to replace instead of SL100 ? because i couldn't find it in my country .
2- what is the program that i can do a simulation to the circuit ?
3-if am going to connected to arduino so i can send a sms using GSM shield , how i can do it ?

thank you
 

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wayneh

Joined Sep 9, 2010
16,292
Just about any NPN transistor or N channel MOSFET will work. It needs to be rated to 10V and at least 200mA. I'd use a MOSFET such as IRF540, which I have on hand, but that is overkill.

Many here use LTspice for simulation. It's free and quite useful.
 

Thread Starter

abdujellah

Joined Apr 24, 2016
5
Can you help me with the simulation?
I tried to take pin 4 high and low as a gas sensor , when i put it high the LED is working but the speaker or the buzzer doesn't work .
 

Thread Starter

abdujellah

Joined Apr 24, 2016
5
I tried to simulate it using Proteus 8 Professional , the LED is working when pin 4 is high but the speaker doesn't .
I didn't find SL100 so i used BFY50 .
what is wrong with it?
 

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Alec_t

Joined Sep 17, 2013
10,928
If the LED is pulsing and R1, Q1 and the speaker are connected correctly then the speaker should make some sound.
 

wayneh

Joined Sep 9, 2010
16,292
Double check you have the right pin out for the transistor.

You should also be able to hear something, I believe, by connecting the speaker to the signal currently going to the base of the transistor. It will be quiet but I would expect to hear something.
 
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