I just have a question about this simple circuit or example: http://www.555-timer-circuits.com/flashing-led.html. I just don't get 1) why do they use 9V battery to power a single red LED light. 2) why there need to be a 1k resistor before the led? 3) does this circuit hugely affect battery's life ( since i try to blink LED to prolong battery life)
Is there anyway to power a 12V LED (current: 0.08A) by 12V battery efficiently (optimal brightness) or i have to use a slightly higher voltage?
Is there anyway to power a 12V LED (current: 0.08A) by 12V battery efficiently (optimal brightness) or i have to use a slightly higher voltage?