This circuit is from the 70s. The integrated circuit used is not common today and the supply is made with a voltage found in televisions of the time, where it was used.
This circuit was found in a 1977 documentation. With it we have the direct indication, through LEDs...
In the figure we have the CMOS logic test circuit developed with the 4049. The circuit activates three...
This headlight reminder for your car was found in the May 1970 issue of Radio Electronics...