This RCA / GE circuit from the 90s can be applied to any modern operational amplifier. The number of entries (installments) can be changed depending on the application.
Found in American documentation from the 90s, this configuration detects the direction of rotation...
Circuits similar to this can be found in this section. This is from 1967 General Electric...
This circuit uses two transistors and can be powered by just two small batteries. The frequency is given...