cool guide.
Looking for throbbing LED scems and brought here.
I am new in electronics, at the level of making led bar.

I wondered if I can connect the figure 12.2D to the led bar I have.
power source 12VDC, led bar 70cm (69 blue leds, package said 5mA each, series of 3, total < 200mA)

and is it possible to expand to 1A, coz I have flex led strip with higher power rating (20mA series) that I want to go to 720mA (180cm in length)

what is the full cycle time, from max brightness to min and max again
I looking for 5 secs for initial and can this be altered ?

really appreciate for a response, thanks
RY

 

Welcome to the forums.

You got your owm thread, as the one you posted in was more informative in nature - http://forum.allaboutcircuits.com/showthread.php?t=19075 , and not a discussion thread.

 

You have any questions I will do my best to answer them. I just revamped several sections, so if you find errors (as opposed to how you would do it, there is always more than one way to do things) let me know.

 

thanks Mod.

Regarding the example 12.2D
is Q1, Q2 and Q3 using transistor 2N2907
and U3b I guess is LM393
CMIIW

what I concern is, if the circuit can handle Led string up to 1 Amp on 12vdc?
thanks

 

Q1 is a NPN (2N2222A or PN2222A), Q2 is a PNP (2N2907A or PN2907A) and Q3 is a nMOSFET.

Most MOSFETs are very high current, and good ones will be around 0.05Ω or less when on. The one Radio Shack carries (IRF510) would work too, though I would hesitate to call it a good MOSFET. It is good enough for 1A.

Don't overlook U3A

 

i.c. U3a and U3b is actually one piece of LM393.
I didn't noticed that before, thanks Bill for the tips to not ignore U3a.
and for the guidance

have to go to downtown 35km away to get this complete list. it will be pain in the ass, to miss any part

I live in Indonesia, half way around the world, so Radio Shack just out of the question