I don't know what is the issue. It was working fine with the red LED with a 9V battery but when I connected it to my car, it just kept strobing without a waiting period. I removed the circuit with the bulb from the car. I will get myself a 12V 2A adapter and test it as it is connected to my car. But I don't know what is wrong with it. I don't know what to test it. Maybe I change the resistors and capacitors with different values. Please let me know if you think something is wrong with my setup. I will specify the materials here for clarification;

• First 555
• resistors are 100k
• capacitor is 22uF
• Second 555
• resistors are 4.7k
• capacitor is 10uF Output pin of second 555 is connected to GATE of an IRFZ44N with a 220 ohm resistor in series. The bleeder resistor between SOURCE and GATE is 10k.

This is the Falstad link of my design

Terminals on right are from top to bottom for the image below;

1. Vcc of the circuit
2. GND of the circuit
3. Drain of the MOSFET

Terminals on right are from top to bottom for the image below;

1. Drain of the MOSFET
2. GND of the circuit
3. Vcc of the circuit

 

hi res.
Welcome to AAC.
Please post a circuit diagram.
E

 

hi res.
Welcome to AAC.
Please post a circuit diagram.
E

I only have a Falstad diagram unfortunately.

 

I don't know what is the issue. It was working fine with the red LED with a 9V battery but when I connected it to my car, it just kept strobing without a waiting period. I removed the circuit with the bulb from the car. I will get myself a 12V 2A adapter and test it as it is connected to my car. But I don't know what is wrong with it. I don't know what to test it. Maybe I change the resistors and capacitors with different values. Please let me know if you think something is wrong with my setup. I will specify the materials here for clarification;

• First 555
• resistors are 100k
• capacitor is 22uF
• Second 555
• resistors are 4.7k
• capacitor is 10uF Output pin of second 555 is connected to GATE of an IRFZ44N with a 220 ohm resistor in series. The bleeder resistor between SOURCE and GATE is 10k.

This is the Falstad link of my design

Terminals on right are from top to bottom for the image below;

1. Vcc of the circuit
2. GND of the circuit
3. Drain of the MOSFET

View attachment 337553


Terminals on right are from top to bottom for the image below;

1. Drain of the MOSFET
2. GND of the circuit
3. Vcc of the circuit

View attachment 337554

I am adding a circuit diagram I just draw from Fusion on request.
It was working when Vcc was 9V and with the LED but when I connected it to 12V (car) and replaced the LED and its resistor with the back fog lamp of my car, it started to stoble continiously.

 

hi res.
Welcome to AAC.
Please post a circuit diagram.
E

I drew and added a diagram.

 

I see a problem with that white wire in the middle.

 

I see a problem with that white wire in the middle.

I think you are talking about that connects 100k resistor with pin-2. What is wrong with it?

 

I don't know what to test it.

If it's strobing continually then the problem is with IC1.
Check all connections on IC1 including pin3 to pin4 on IC2

 

If it's strobing continually then the problem is with IC1.
Check all connections on IC1 including pin3 to pin4 on IC2

I will try it when I get a 12V adapter. I probably get it tomorrow.

 

Wait a minute. Are you saying it works with the 9 volt and LED on that perfboard as wired?

 

Wait a minute. Are you saying it works with the 9 volt and LED on that perfboard?

I connected 9 volt battery and LED via terminals. And yes it was working fine.

 

I connected 9 volt battery and LED via terminals. And yes it was working fine.

Try adding diodes D1,D2 and caps C3,C4 for isolation and filtering.

 

Try adding diodes D1,D2 and caps C3,C4 for isolation and filtering.
View attachment 337567

I will try it but what should be capacitance of the c3 and c4?
I have 1N4007 on my hand. Is it okay for D1 and D2?

 

I will try it but what should be capacitance of the c3 and c4?
I have 1N4007 on my hand. Is it okay for D1 and D2?

22uf and 1N4007 OK.

 

I guess that is an interesting problem. Unfortunately I have no idea as to what a Falstad diagram is, or what it tells me.
I have not yet adequately evaluated the circuit schematics.
And the actual complaint is a bit confusing to me.

 

I guess that is an interesting problem. Unfortunately I have no idea as to what a Falstad diagram is, or what it tells me.
I have not yet adequately evaluated the circuit schematics.
And the actual complaint is a bit confusing to me.

It should work like this. Instead it is constantly flashing. As for the Falstad diagram, I don't think it is a legit diagram. It is a website that simulates your circuit with time. I drew this circuit there first then I added a Fusion diagram in the comments. They are both identical.

 

I think you are talking about that connects 100k resistor with pin-2. What is wrong with it?

My post was meant to be tongue-in-cheek!

Here is what I would do differently:

1. Use 30 AWG wire wrap wire.
2. Use different colours to help identify wire function.
3. Don't put more than one lead or wire in a hole.
4. Use Vero strip board (Veroboard) instead of single pad solder points.



Even this is better than what you are using.




Before building a project on a circuit board, you should test it out first using a solderless prototyping board.

 

Read what the TS said in post #11.
Apparently just not working correctly in the vehicle.

 

I suggest adding 0.1 mfd capacitors across the input power connections (pins 1 and 8) of each 555 IC. The symptom is power fluctuations causing unwanted coupling between the two ICs.

 

Similar to what MisterBill says, I would suggest adding 1-10μF across pin-1 and pin-8 of both NE555 ICs and 47-100μF across the power supply rails where they enter the board.