This traditional configuration with the 555 was obtained in an 80s Hands-On Electronics. The relay is of the sensitive type according to the supply voltage.
The circuit shown was found in an American documentation from 1964. The circuit uses transistors of...
We found this antenna amplifier or Booster circuit in an Electronics Now from the 90s. The circuit...
This dimmer with a unijunction transistor and SCR appeared in Radio Electronics magazine in March...