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General Category => General Discussion => Topic started by: Kamel85 on April 08, 2015, 18:24:54 PM

Title: Breathing LED 555 circuit
Post by: Kamel85 on April 08, 2015, 18:24:54 PM
Hi.

I have tried making this circuit but my led just keeps lighting.
I have re-built it several times, thinking i made some mistake connecting it, but same isue led is just on.
I tried with different 555, bc337 and 2n2222 but no luck, any ideas what i might have connected wrong?

Thanks /K

Update, I found the issue by replacing R4 100k ohm with a 1m pot, value needed for circuit to work was 1.3M ohm
Title: Re: Breathing LED 555 circuit
Post by: Kamel85 on April 14, 2015, 15:05:37 PM
I have another issue, i have now built the circuit on a perfboard but its very dim, maybe 25% as bright as the one on the breadboard with same led and powersupply.
exact same values of resistors, diodes, transistors etc are used
Any idea what component might be damaged?
Title: Re: Breathing LED 555 circuit
Post by: cheerio on April 18, 2015, 20:39:24 PM
maybe the led is done. they tend to lose brightness when they die
Title: Re: Breathing LED 555 circuit
Post by: kam on May 01, 2015, 12:58:03 PM
oh yes as cheerio said, make sure that the maximum voltage does not exceed the vfd of the led. As a matter of fact, better measure the max current through the led