I am trying to build a circuit to flash, alternately, 2 LEDs, with something close to a 50/50 duty cycle (which I have read is a bit complex for the 555, but anything close is fine, no need for perfection in this case) at somewhere around 5-10 flashes per second. I have a circuit that seems to work, and I can get the LEDs to flash, but the problems I am having are:
(1) How do I get the appropriate flash rate that I am looking for? I know changing the resistor and/or capacitor values will change the rate/cycle but how exactly do I figure out what resistors to use?
(2) After about 10 seconds or so, the LEDs stop flashing and remain steady, both lit, one very dim, and the other at a normal level. If I disconnect the power for a minute or so, and then reconnect, I get the same problem. If I disconnect power for only a second or two, then reapply the LEDs will flash a few more times, but then stop.
I am using high power 3-watt LEDs, could this be a major problem? (The resistors for the LEDs themselves are 5W 27Ω resistors which get a bit warm, but not hot while running). The supply voltage is 12v from a battery, and I am currently using a 2.2kΩ R1 and a 1MΩ+470kΩ series for R2, with a .1μF capacitor (these will end up being changed, I am sure in response to part one of my question).
This is the diagram I am using:
Thanks in advance to any and all help! If you can only answer part of my question, that is perfectly okay!
(1) How do I get the appropriate flash rate that I am looking for? I know changing the resistor and/or capacitor values will change the rate/cycle but how exactly do I figure out what resistors to use?
(2) After about 10 seconds or so, the LEDs stop flashing and remain steady, both lit, one very dim, and the other at a normal level. If I disconnect the power for a minute or so, and then reconnect, I get the same problem. If I disconnect power for only a second or two, then reapply the LEDs will flash a few more times, but then stop.
I am using high power 3-watt LEDs, could this be a major problem? (The resistors for the LEDs themselves are 5W 27Ω resistors which get a bit warm, but not hot while running). The supply voltage is 12v from a battery, and I am currently using a 2.2kΩ R1 and a 1MΩ+470kΩ series for R2, with a .1μF capacitor (these will end up being changed, I am sure in response to part one of my question).
This is the diagram I am using:
Thanks in advance to any and all help! If you can only answer part of my question, that is perfectly okay!