Hi,
I am attempting to make a electronic cigar lighter. I am using a FeCrAl metal heating element to do so:

I am using a 555 timer with a push button, alongside a irf3205 Mosfet, to actuate and heat the element.

The problem I run into is this:

What I believe to be some poor connection with the mosfet that is causing it to heat way above its threshold temperature and melting both itself and my breadboard. The blue wire also melts alongside it.
After doing research, I came to the conclusion that this is a poor circuit connection issue because that is what commonly causes this melting.

My question to everyone:
How can I solve the issue of the melting components in my breadboard? Must I solder everything together? Is this the problem?

Thank you.

 

Most of the components can be on you breadboard EXCEPT for the main power circuit. Your breadboard can't handle that kind of current. The load must see a low resistance (not breadboard) path to both ground and the power supply. This path is mediated by the MOSFET, so you need solid connections of the MOSFET to the power bus. That should be fat pieces of wire, not a delicate breadboard. Only the gate can be in the breadboard part of the circuit.

 

Most of the components can be on you breadboard EXCEPT for the main power circuit. Your breadboard can't handle that kind of current. The load must see a low resistance (not breadboard) path to both ground and the power supply. This path is mediated by the MOSFET, so you need solid connections of the MOSFET to the power bus. That should be fat pieces of wire, not a delicate breadboard. Only the gate can be in the breadboard part of the circuit.

Makes sense. Thank you.

 

What voltage are you using on the MOSFET gate? It needs 10V to turn on fully. Using less than that will cause it to overheat.

 

What voltage are you using on the MOSFET gate? It needs 10V to turn on fully. Using less than that will cause it to overheat.

That is very key. I did not know that and it was definitely under that

 

I don't use those plastic plug-in breadboards and solder everything. That solves a lot of problems. I suggest that you do the same.

 

That is very key. I did not know that and it was definitely under that

If you need a lower gate voltage. look for a logic level MOSFET. They typically are fine at 5V and some as low as 3V. The IRLZ44N is a common one. Note the ‘L’ in the number, there is also an ‘F’ version that needs the usual 10V.

 

By the way, those plug-in breadboards are only good for a couple hundred milliamps if that. They are for small signals.

 

If you need a lower gate voltage. look for a logic level MOSFET. They typically are fine at 5V and some as low as 3V. The IRLZ44N is a common one. Note the ‘L’ in the number, there is also an ‘F’ version that needs the usual 10V.

Okay. That’s info I needed. Going to save me a headache. Thanks so much.

 

By the way, those plug-in breadboards are only good for a couple hundred milliamps if that. They are for small signals.

How do you make everything organized? Is there some type of solder board that I can replace my breadboard with while still using the old breadboard resistors and such?

 

How do you make everything organized? Is there some type of solder board that I can replace my breadboard with while still using the old breadboard resistors and such?

You might try something like this:
https://www.amazon.com/dp/B07FK3Q6FV/ref=sspa_dk_detail_2

Note there are many different sizes and prices out there.

Personally, I like to plan mine out completely before I start soldering. If you want to do that, and you have experience with drawing programs, I can provide a template that would be helpful to get started.

 

You might try something like this:
https://www.amazon.com/dp/B07FK3Q6FV/ref=sspa_dk_detail_2

Note there are many different sizes and prices out there.

Personally, I like to plan mine out completely before I start soldering. If you want to do that, and you have experience with drawing programs, I can provide a template that would be helpful to get started.

I do not have much experience with circuit drawing programs. I have a fundamental circuit background. I would appreciate that template either way. Thank lots.

 

I do not have much experience with circuit drawing programs. I have a fundamental circuit background. I would appreciate that template either way. Thank lots.

Take a look at my project here for samples: https://forum.allaboutcircuits.com/threads/micro-current-electrical-stimulation-device.126578/
As I noted there, I'm happy to share the file if you think you can use it but I'm probably the only person here using that application.

 

I do not have much experience with circuit drawing programs. I have a fundamental circuit background. I would appreciate that template either way. Thank lots.

I tend to plan things out in my head and then carefully add the parts to a small donut-per-pin circuit board such as that used by @wayneh

 

Take a look at my project here for samples: https://forum.allaboutcircuits.com/threads/micro-current-electrical-stimulation-device.126578/
As I noted there, I'm happy to share the file if you think you can use it but I'm probably the only person here using that application.

Took a look. Got a better idea of the soldering board now.
You mentioned: 'The load must see a low resistance (not breadboard) path to both ground and the power supply. ' Does that mean that I need to have a low ohm resistor (like 50 ohms) on my 3.7V 2500mAh attached in series from both its positive and negative terminals to the board?
Also, in the example post, I see the pictures of the components in the board, but I do not see the soldered wire connection between the components that were shown in the concept design photo. Are the soldered connection wires under the board? In other words, how do you connect each pin on the board in a wire manner?

 

Do you guys recommend an online electronic service other than digikey or Amazon?
The problem I have with digikey is the $7 shipping cost each time I buy.
And with amazon, most things are bought in bulk.

 

Took a look. Got a better idea of the soldering board now.
You mentioned: 'The load must see a low resistance (not breadboard) path to both ground and the power supply. ' Does that mean that I need to have a low ohm resistor (like 50 ohms) on my 3.7V 2500mAh attached in series from both its positive and negative terminals to the board?

No, you need fat wires that can carry current without getting hot. The thin conductors of the breadboard are not meant for even one amp of current.

Also, in the example post, I see the pictures of the components in the board, but I do not see the soldered wire connection between the components that were shown in the concept design photo. Are the soldered connection wires under the board? In other words, how do you connect each pin on the board in a wire manner?

The wires are there. For short distances, I try to bridge "donuts" on the backside of the board. Those are the blue lines in my drawings. Part of the layout challenge is placing everything to make the interconnects as easy as possible. For instance if you can line up 8 donuts in a row that are all at ground, you can lay a bare wire across them and tack it down to the donuts. I try to minimize the wires that are added to the topside since that is the most tedious part of the build and makes things ugly. They're unavoidable until you advance to a premade printed-circuit-board.

 

No, you need fat wires that can carry current without getting hot. The thin conductors of the breadboard are not meant for even one amp of current.
The wires are there. For short distances, I try to bridge "donuts" on the backside of the board. Those are the blue lines in my drawings. Part of the layout challenge is placing everything to make the interconnects as easy as possible. For instance if you can line up 8 donuts in a row that are all at ground, you can lay a bare wire across them and tack it down to the donuts. I try to minimize the wires that are added to the topside since that is the most tedious part of the build and makes things ugly. They're unavoidable until you advance to a premade printed-circuit-board.

Understood. Thanks lots.

 

No, you need fat wires that can carry current without getting hot. The thin conductors of the breadboard are not meant for even one amp of current.
The wires are there. For short distances, I try to bridge "donuts" on the backside of the board. Those are the blue lines in my drawings. Part of the layout challenge is placing everything to make the interconnects as easy as possible. For instance if you can line up 8 donuts in a row that are all at ground, you can lay a bare wire across them and tack it down to the donuts. I try to minimize the wires that are added to the topside since that is the most tedious part of the build and makes things ugly. They're unavoidable until you advance to a premade printed-circuit-board.

What gauge wire should I get for the thicker wire you mentioned?

 

What gauge wire should I get for the thicker wire you mentioned?

How long do they need to be and what is the peak amperage? Standard lamp cord is probably overkill but let's see.