This simple Bargraph photometer with 4 LEDs was found in a 1997 documentation. The scale is adjusted in a trimpot and the sensor can be any common LDR. Power can be supplied by cells or battery.
The MOS field effect transistors of this circuit are not very common, as it is a project from the...
If interference occurs in several receivers, much more interesting than placing a filter on each...
This single-cell Li-Ion battery charger was found in a 2005 Linear Technology manual. The circuit...