This extends my previous question involving same circuit, information replicated here for convenience and independence of this question.
The following circuit schematic:
Has been connected as shown here:
However, on connecting it to the power source (now a 12VDC lead-acid battery, with unloaded terminal voltage as bit over 13VDC, from a robotics kit), I see that only the green LED is glowing (permanently lit), and red LED is unlit. The expected behaviour is both flashing alternately (aka Railroad crossing lights). What all could be wrong here ?
Best Answer
The circuit itself is fine as long as there's enough headroom for the output to swing between 1/3 and 2/3 Vcc, and that's not a problem with a 12 volt supply and little LED loads.
According to LTspice, the circuit should work, so the only things I can think of are that maybe your wiring is different from what you've shown or you've got a bad 555.