This circuit was obtained in a magazine for radio amateurs 73 of the 90s. The circuit is based on the XR2206, which is not a component found easily today.
This amplifier with very high input impedance was suggested by Texas Instruments in a manual of...
Using only a ULN5804 integrated circuit, stepper motors up to 500 mA can be controlled from TTL...
Constant current sources are used in applications such as battery chargers, electrolytic tanks, etc....