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i can't figure out this schematic... can you help?

forrest mims "dual LED flasher". Can't get it right. put it together about 10 times now. no blinking. LEDs are just constantly on

Picture of i can't figure out this schematic... can you help?
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mcmahanly (author) 6 years ago
Hey everybody. Thanks for replying. That is what makes this website so great. Anyhow, about the schematic, I finally got it working. Believe it or not, I had a faulty bread board! I discovered this only by chance. There was something wrong with the power buses and the circuit didn't work until i condensed everything down into one corner of the board. Imagine that. I've put it together and taken it apart multiple times and I am now working on soldering it all together. Thanks for your help everybody! Let me know if there is anything I can help you with.
May not be defective. Some solderless breadboards group only part of the busses -- carrying them only halfway down, for example, and expecting you to add a jumper connection if you want to extend the power bus all the way down that side.

(This is because there may be more connections worth putting onto the busses than just power, and dividing them up gives you more flexibility at the expense of some loss of convenience.)
You might want to look at the answers for this question:
https://www.instructables.com/answers/How-to-read-a-Forrest-Mims-schematic/

The circuit in that question looks very similar to the circuit you've posted for this question.
;-)
mcmahanly (author)  Jack A Lopez6 years ago
I posted that question as well :) same circuit we're dealing with... just trying to reach out to as many people as I can. thanks for the help.
orksecurity6 years ago
If the answers to the other copy didn't help you, find someone local to you to look at what you built and help you debug it.

(To Re-designs answers I would add: Or you were sloppy with the soldering iron and cooked one of the components. That's one reason I don't use anything larger than a 25W soldering iron unless I'm dealing with something that Really Needs The Additional Heat.)
mcmahanly (author)  orksecurity6 years ago
Thanks, but it is all on the breadboard. I try not to solder until I figure out the circuit.
The power of the iron is much less important than the temperature - all mine are 120W plus, but temperature controlled.
... which essentially means you're putting less wattage through it than the maximum it's rated for. But, yes, valid point.
Re-design6 years ago
If you can't get it to work like it is supposed to and someone else on your other question did, then...

1.  One or more of your parts is bad.
2.  One or more of your parts are the wrong value for the circuit.  Yes I know you followed the parts list exactly but part have a tolerance.  Substitute the resistors etc.
3.  You have a wiring error.  Yes, I know you have followed the diagram exactly but this is very often the problem.
4.  The electronic gods just don't like you.  This is the least likely answer since the electronic gods are the most loving and caring gods of them all.
P.S. Where did you find this as an e-book???
mcmahanly (author)  Re-design6 years ago
I have the real book. I just googled the book title and searched for a pic of the schematic. it is out there though.
Yes, same guy, same question, doesn't like the answers.