1.5 volts LED flasher for full year ??? is it possible

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Both of those circuits blink a tiny red LED once every second or two. If you aren't staring at it, you will miss it.

A white LED needs almost twice the voltage. Even if you doubled the voltage you would not like a torch that gives a weak blink every two seconds.
 
You have to look at it to be able to know it glows, if at all it works with 74HC series. These types need Vcc min of 2V to work. check the relevant data sheet at ALLDATASHEET.COM - Datasheet search site, Datasheet search site for Electronic Components and Semiconductors and other semiconductors.

However you may Google for single transistor based Joule thief, it works, but may not be for an year.
 
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Hello all,
I might be missing something but I do not understand how this circuit can operate...
The forward voltage drop of most LED's is about 2v +-... your Battery is only 1.5 volts...
It appears to me the LED will not turn on...
If that is correct, you will need two batteries to have a chance.
Hope this helps.
 
mesafloyd said:
Hello all,
I might be missing something but I do not understand how this circuit can operate......
Click to expand...

You are missing the voltage-doubling action of charging the large capacitor to the battery voltage, then switching it in-series with the LED to double the applied voltage to the LED, and letting the capacitor discharge through the LED.
 
It might be better to use a Joule Thief circuit since it will extract virtually all the energy from a battery.
 
Propabaly time to ask "what is he trying to do"... too many variables. Duration/brightness(and color)

Bottom Line... power density is power density... (Only so many electrons available in any given battery power source.)
Then apply the math before soldering components. At least you have a rough idea of the outcome...
Floyd
 
I made some LED flashlights with different coloured LEDs and powered from a 9V battery. The battery lasts for a long time because my circuit blinks the LED very brightly but for short duration pulses 5 times then a pause before blinking again. The bursts of 5 pulses occur once per second. The LED is turned off for most of the time but I can see fine at night on walks and at the barbeque.
 
I made a school project back in the 80s using an LM3909 flasher IC for door signalling systems on the admin offices.

I went back 10 years later when I was working for myself to service their computers and it was still going on the original batteries
 
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