This circuit for AC loads was found in February 1976, Radio Electronics magazine. The triac is common, and the times are given by the 20 MΩ resistor and the 1 uF capacitor.
In the figure we have a simple logic level indicator for TTL circuits or powered by 5 V....
This circuit was obtained from the December 1990 issue of Radio Electronics magazine. The circuit...
This power supply for gas laser (HeNe) was found in a 90’s Popular Electronics. It generates from 1300...