This circuit was obtained in a documentation from the 80's. However, using TTL it is still modern, being able to be used as Shields for microcontrollers or part of digital projects.
Found in Linear Technology documentation, this circuit drains only 70 uA of the monitored circuit....
120 degree lagged signals can be obtained with the simple configuration shown in the figure....
This circuit compares two light intensities, providing the indication on an analog instrument. The...