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 the Linear Applications Handbook of the National Semiconductor of 1994....
This circuit for antiparallel control of thyristors was found in a Philips publication from 1967....
The purpose of this circuit found in a 1995 magazine is to monitor an alarm via telephone. When we...