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General Category => General Discussion => Topic started by: Warren Weiss on November 03, 2016, 00:02:26 AM

Title: Flexible 555 LED Pulsing (Breathing) Circuit
Post by: Warren Weiss on November 03, 2016, 00:02:26 AM
After completing this fabulous circuit by Giorgos Lazaridis http://www.pcbheaven.com/userpages/Flexible_555_LED_Pulsing_Circuit/ (http://www.pcbheaven.com/userpages/Flexible_555_LED_Pulsing_Circuit/), I tested it and everything works as it is supposed to except I can't get more that about 2.2 volts maximum from the output.  The only deviation from the component list is where I substituted a PN2222a for T1 and used a 500K trim pot instead of 470K for R7.  I've checked the wiring, connections, and components (for correct values) multiple times.  Perhaps one of the components is defective, but I'm not really sure where the problem could be.  Substitution of components for individual testing will be extremely difficult as I did not use a breadboard.  For this reason I would appreciate any suggestions of where to start looking, starting with the most likely issues!
Title: Re: Flexible 555 LED Pulsing (Breathing) Circuit
Post by: kam on November 06, 2016, 10:50:15 AM
You can try a smaller R4 or try bigger R5 to get higher output.
Title: Re: Flexible 555 LED Pulsing (Breathing) Circuit
Post by: Warren Weiss on November 19, 2016, 09:34:58 AM
I just replicated the circuit on a breadboard using the substitute parts (PN2222a transistor for T1 and 500K ohm trim pot for R7) and can report that the circuit works as advertised without further modification.  Not sure if I made a mistake on the original circuit or if I used a faulty component.  Just want to let everyone know that a PN2222a will work as a substitute for the BC338.
Title: Re: Flexible 555 LED Pulsing (Breathing) Circuit
Post by: kam on November 23, 2016, 09:29:41 AM
Good Job!