This comparator circuit was found in the May 1988 Radio Electronics magazine; The power supply does not need to be symmetrical.
This circuit suggested by Siemens can provide time intervals for triggering values that are given...
This is one of the first transistorized receivers (2N107) published in the Radio Electronics...
This circuit is from a 1967 publication. It is possible to power a fluorescent lamp from a 12 V...