This alarm goes off if someone leaves a door open. We found it in the Encyclopedia of Electronic Circuits Volume 5 from 1995. The circuit uses components that are still common today.
The LM1468L can also be used. The circuit is from Motorola's Linear Interface ICs and the...
This shield circuit for controlling the direction of rotation of DC motors with current up to 500...
This circuit can be used to control loads up to 500 mA from the outputs of microcontrollers such...