LED Flasher

[KJ6EAD]

This thread should probably be moved to "Homework Help".

 

[4pyros]

Hello, I am looking to flash 36 LED's, actually want to use a switch to flash them with the other state being solid. I've gotten a start from this forum and have a 555 timer. I'm not skilled with this but it appears I need a SPDT switch where one side will send the power through the 555 timer and on to the LED's, and the other side of the switch will bypass the 555 timer all together? (I thought the other side should go thru another 555 timer in monostable mode but this seems to only be for a timed period)

The LED's are 5mm, 3.8v and 30mA. I've figured out the parallel setup and resistors to use.

Next issue is hooking up the 555 timer for astable state - any suggestions on where I can learn how to do this. I've looked at the schematic but need some training.

Thank you,
Frank

Frank; Start your own post.

 

[audioguru]

36 LEDs at 25mA each (30mA is the max allowed current when they burn out soon) is a total current of 900mA.
But the max allowed output current from a 555 is only 200mA when it gets very hot because it causes a huge voltage drop.

You must use a power transistor or power Mosfet to turn on the LEDs and the 555 can turn it on.

 

[4pyros]

Frank; Start your own post.

 

[Frank88]

Thank you for the helpful responses. I've moved my post to Homework help under "Toggle LED's between blink and solid"
Frank

 

[colin55]

The circuit does not work.
This is another: https://www.redcircuits.com/Page64.htm RED CIRCUITS that has never been tested.

 

[audioguru]

The circuit does not work.
This is another: https://www.redcircuits.com/Page64.htm RED CIRCUITS that has never been tested.

I like the way that "nothing" turns off the second transistor.