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Author Topic: Help request: soldering a 555 circuit board for a strobe  (Read 126 times)

Offline greg

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Help request: soldering a 555 circuit board for a strobe
« on: November 19, 2017, 07:11:23 am »
Could anyone please help me?

I have successfully built a strobe light on my breadboard, but when I attempted to solder up a circuit board for it, I only get a solid light.
Here is a video showing what I have done. Can anyone give me any advice? I can only think that perhaps the diode is polarized and that I have it in backwards. Or maybe the capacitor, but I am pretty sure it's aligned the way it was on the breadboard.

Advice would be greatly appreciated. Thank you!

Offline Spencer

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Re: Help request: soldering a 555 circuit board for a strobe
« Reply #1 on: November 19, 2017, 09:24:30 am »
Taking a quick look at your video, I think you might have the capacitor soldered on backwards.
Try flipping it around.

Offline Cpt-Spekkie

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Re: Help request: soldering a 555 circuit board for a strobe
« Reply #2 on: November 19, 2017, 11:25:42 am »
Hey Greg, Like i commented on Youtube and Spencer noted here, the capacitor is definably backwards.


Offline greg

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Re: Help request: soldering a 555 circuit board for a strobe
« Reply #3 on: November 19, 2017, 10:03:55 pm »
Thanks for the feedback, guys. YouTube comments have confirmed my suspicion that the diode is indeed polarized. I took several pictures of my breadboard setup and I definitely have the diode in backwards as compared to before. The black end should be on the right side instead of the left. People have also said the same that I probably have the capacitor in backwards too. That's strange, since I was pretty sure I had it in the same way as before.

So I guess what I have to do is heat up those contacts again to loosen up the solder and pull the wires out? I don't own a solder sucker. I'll check my local home center to see if they have anything like that.

Offline greg

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Re: Help request: soldering a 555 circuit board for a strobe
« Reply #4 on: November 20, 2017, 03:35:22 am »
I reversed the diode, so now the black band is on the right. It now works! I guess I lucked out the first time around on the breadboard because I didn't know about this. Thanks!

Offline Spencer

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Re: Help request: soldering a 555 circuit board for a strobe
« Reply #5 on: November 21, 2017, 06:59:52 am »
Nice to know it all worked out.

In case you were unaware, (most) diodes only allow current to flow one way, so direction is important ...

Offline greg

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Re: Help request: soldering a 555 circuit board for a strobe
« Reply #6 on: November 21, 2017, 06:01:38 pm »
Thanks again, everyone. I was able to make another strobe circuit last night rather quickly. It's cleaner and I fit it onto a smaller board now that I have the experience. I tested it and it works! Very happy.

Offline Markeno

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Re: Help request: soldering a 555 circuit board for a strobe
« Reply #7 on: December 02, 2017, 12:06:16 am »
I had never seen a diode used in a 555 circuit that way.

You can think of a diode as a one way wire.  Electric can go one way through it but not the other (unless there is too much, and it can then force through the diode typically destroying it).  If it was backward, it was making that flow the opposite of what it was supposed to.

It is rather late, so I may have the rest of this "backwards" myself, but it would be the way I say or the opposite just like your diode had been. Disconnected for Connected, Charging for Discharging, increase for decrease..

Without watching the video, and based on the strobe/flashers I have used with 555s, my thought was it to be the capacitor was in wrong or had failed.  If the capacitor is disconnected/missing it stays on constant.  What you had was the Capacitor was not Charging due to the diode being installed in reverse. 

When the capacitor charges our LED goes out.  It will stay out until the capacitor is drained.  Once it is drained, the LED will come back on, until it finishes charging again.. repeat.  Increasing the micro/nano/pico fared rating  of the capacitor slows down the cycle.  Also increasing the value of one resistor will slow down the charge, while changing the other will slow down the discharge in the 555 flashers I use that don't include that diode.


I am going to have to hook up a 555 with a diode there and see how it changes the operation.  The 555 can be fun to work with, it is always cool to find something a little different to do with it.

Offline greg

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Re: Help request: soldering a 555 circuit board for a strobe
« Reply #8 on: December 06, 2017, 09:46:31 pm »
The diode is required to make the light strobe. Otherwise, the 555 chip cannot keep the light dark for so long. The capacitor worked while backwards and it was the backwards diode that was in wrong, but I went ahead and fixed both.

 




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