This sensitive motion sensor with inductive sensor was found in a 90s Elektor. The circuit uses only transistors to activate a buzzer.
Found in a 90s General Electric documentation, this circuit has a drain current of just 1.5 uA....
This circuit divides the voltage of a source by 2, allowing its use as a symmetrical source. In...
This low-pass filter with 741 op and symmetrical source was found in the August 1993 issue of...