This diagram was found in the November 1972 issue of Radio Electronics magazine in an article describing benchtop equipment. The transistors are of the time and the frequencies are given by the coils.
This two-phase stepper motor circuit was found in an old documentation using an operational amplifier...
This circuit is suggested by National Semiconductor and with two operational amplifiers an LM833...
This circuit is from the September 1985 issue of Radio Electronics magazine. The circuit has an...