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LED Schematics

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New Member
Hi, everybody.

I am not that technically advanced in the field of electronics, just got started.

My intention is to build a cluster of LED's to be used as running/brake light in the tail light of my motorcycle.

I want to use between 18-36 LED's.

How do I calculate the resistance needed for them, do I need any transistors or capacitors?

And finally: is it best to do rows of LED's in series or parallel?

I appreciate your help.



New Member
I forgot to ask: is there a specific voltage I should use for the LED's?

Right now I have 3V Led.


New Member
TNT said:
I forgot to ask: is there a specific voltage I should use for the LED's?

Right now I have 3V Led.
u really need an anser?

as for series or parallel, id go for both (e.g 8 parallel with 3 in series


Well-Known Member
Most Helpful Member

Have you ever seen a motorcycle with a big snow-plow blade, and a flashing blue strobe-light? :D :D


New Member
This should help....I know it says six volts and your bike is 12v.
run a search ot the web for
"555 calculator" and "LED resistor calculator" (bill bowdens is good)
these will allow you to adjust certain values to get it running
The 555 timer is fairly robust device and will run happily on 12v

The supply rail from the the alternator to the battery is subject to fluctuations , check your supply voltage! 18volts is not unheard of in an automotive / motorcycle charging circuit. The 555 will run at 15v , but any more u will be pushing your luck.


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