This circuit was found in a 90s Popular Electronics. It is possible to analyze the voltages of an automotive battery. The integrated voltage comparator circuit admits equivalent.
Found in a magazine 73 for radio amateurs, this circuit has two settings, one for the interval and the...
This good quality amplifier found in a 1982 documentation has a traditional complementary output...
A low frequency divider can be made using common unijunction transistors as shown by the figure...