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.
We found this circuit in a publication from the 1980s. It can function as a touch switch and if...
The figure shows how to implement an inverter trigger using the LM3900. The LM3900 is a NORTON...
In this circuit we have the way to obtain a pseudo sequential effect of LEDs using 3 FETs. The...