This circuit was found in a 90s EDN. In it we have the use of LEDs and diodes to stabilize the supply voltage of a CMOS load.
This intercom uses transistors from the 60s. It was found in a Japanese publication at the time....
A The adjustable Q-factor rejector filter in the figure is based on two LM110. These integrated...
Found in Electronics Now this circuit can generate signals up to a few tens of Megahertz. The circuit...