This circuit was obtained in a Hands-On Electronics from the 90's. The circuit turns on one LED at the end of the timer, erasing the other. The timing can be increased by changing C1.
In the figure we have the way to trigger a 7555 CMOS monostable with a positive pulse. The time...
This circuit is from a 1968 documentation. It generates a non-symmetrical signal with the waveform...
This circuit is from the manual of the used operational amplifier itself. The same setting can be...