For experiments with a disk rotating at various speeds, the April 1998 Electronics Now magazine suggests this PWM motor control. The current with the LM317 is 1.5A maximum.
This is a 6-transistor transistor receiver manufactured in the 60s. The circuit is a...
This circuit is from a 2005 Linear Technology publication. It converts current into load sensing...
The circuit in the figure is an amplifier with gain 10 for alternating signals using the 741. The...