This circuit activates a relay after a time given by C1 and R1. The circuit is from a Radio Electronics from December 1974. The relay voltage is the same as that used in the power supply.
This general-purpose transistor amplifier stage was found in the November 1993 issue of...
The integrated circuits suggested in this project are double equivalents of the well-known 555....
This shield can be controlled by positive or negative voltages of the sensor acting as a...