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.
We found this simple circuit with headphones listening in Radio Electronics magazine from March...
This circuit was obtained from Maxim documentation. The circuit has 4.5 and 5.5V thresholds for...
This complementary-output amplifier can be used to source a good qualuty signal to high impedance...