Hello, thanks for the reply. In the second circuit the green LED should light up when the red goes out. Do I need two timers then? I will look at the link you provided.
@SunnySkyguy: Thanks, neither precision nor cost is a factor here.
No problem.
SW1 looks like it is for 10 sec. False Start. ( Red Only)
SW2 looks like a GO after 10 sec and Off when SW2 is turned off.
Current limiting resistors can be on either side of LED to +5.
High bright Red LEDs are ~3V, Green ~3.5 and current limit is Ohm's Law on voltage drop from 5V. So 100 Ohms min for Red, 75 OHms min for Green for 20mA.
R for low intensity could be 470 Ohms or anything in between.
Not all 555's are the same but some indicate 10s requires 10uF & 1MOhm or similar CR product. i.e. 1uF x 10 MOhm
Not all 1uF caps are the same either and many do not support a time constant longer than 0.1s with 1~10uA of leakage, so a low leakage cap is required which costs more , plastic is best, but Tolerance is usually poor (20%)
Where you get your parts and which type will affect the results significantly.
- - - Updated - - -
If the green LED should light up -and still lighting- when the LED is off then one 555 timer is enough. So the circuit output should looks like:
**broken link removed**
And the RC values are the same as I said before.
But note that the green LED starts on. If you want it to start off then after red LED is off it lights up, then the circuit is different.
- - - Updated - - -
LED resistors could be any suitable value like 470 ohm.
Show him how to connect the 2 switches so they both go off.
Not
all 555's use this time constant of 1.1 RC.