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 increasing C1.
Settings like this can be found at various points on this site. The trigger door can be a 4093...
Toshiba LDO Regulators Toshiba has a wide variety of low voltage drop (LDO) linear regulators...
With a 10 V input this circuit provides a 25 V output. The circuit is from December 1985 Radio...