This lockable two-position servo control system was found in documentation from the 1990s. The error amplifier can be an operational amplifier and the sensors are phototransistors.
This 1969 Philips documentation circuit makes it possible to control an engine through the sound...
We find this circuit in the manual of the used integrated circuits. The manual is from Linear...
This circuit can be used as a residential doorbell. We found it in an English publication from...