The motors are powered by small current amplifiers constructed from LM675 power operational amplifiers. The circuit diagram is shown below. With a power supply of +/- 12 volts and a D/A output of +/-5 volts, the amplifiers generate a minimum current of 1.5 amps (the maximum rating for this motor). This results in a maximum motor torque of 0.035 N-m, which corresponds to a force of 7.5 N at the joystick handle.

Electronic Elements	Other Parts
1 k-ohm resistor	Heat sink for LM675
10 k-ohm resistor	Nylon screw and nut to attach heat sink to LM675
2 x 1 uF capacitor	Screw terminals and Molex connectors
22 uF capacitor (non-polar)	Perf board for mounting components
0.33 ohm power resistor (> 3 Watts)	Power supply with +/- 12 volts and 2 Amps/kit
1 ohm power resistor
LM675 Power op-amp

Allison Okamura - allisono@cdr.stanford.edu
© 1998