loading
6Comments

Tell us about yourself!

Complete Your Profile
  • LukeK17 commented on Trilesto's instructable Flashing L.E.D. using 555 Timer10 months ago
    Flashing L.E.D. using 555 Timer

    I should have mentioned that most LED's can safely (without burning out) handle around 20mA of current. So, if you're using a 12V supply, keep the resistor value above 510 Ohms. Note: 12 / .020 = 515, but using 510+ won't hurt)

    Providing your capacitor is rated for 12V+, you wouldn't need to change anything. Remember, the voltage at pin 3 is roughly 1.7V less than VCC - so, 10.3V. Using the same 1K resistor, you'd be putting 10.3mA through the LED, which is fine. It will just be a little brighter. OHM's Law, my friend. :)

    I should have also mentioned that most LED's can safely (without burning out) handle around 20mA of current. So, if you're using a 12V supply, keep the resistor value 510+ Ohms. Note: (12 - 1.7) / .020 = 515, but using a 510+ Ohm resistor won't hurt.

    On a 555 IC, pin 5 is 'Control Voltage'. It isn't used in this case (don't connect it to anything).

    View Instructable »