The indicated circuit uses an unusual buffer from National Semiconductor. The frequency is given by resistors R1 and R2 as well as capacitors C1 and C2.
We found this logical configuration in a documentation from the 1970s. It consists of a...
This circuit uses a dedicated Philips integrated, which consists of a stepper motor control from 3...
This circuit trips with negative pulses and the value of C depends on its intensity. C1 determines the...