🚀 go-pugleaf

In article <1993Jan25.135100.46744@kuhub.cc.ukans.edu> rsl09@kuhub.cc.ukans.edu writes:

>  I am interested in a power amplifier that could drive a DC motor/actuator.
>I am using the actuator in a slow-response feedback loop. The power amplifier
>should interface an OP-AMP, that produces the error signal, and the
>actuator that demands up to 3 Amps for input voltages up to 20 volts.
>Therefore, I need a push-pull 60 W DC power amplifier. I have been able
>to find couple of power OP-AMPs that seem to to able to do the job. But,
>they are expensive - price is around $100. 

	And, power op amps can usually NOT handle an inductive load
(like a motor).  They will burn up (no, internal current limiting
is NOT a solution here: the problem is reverse-biasing the output
transistors' emitter junction, and kills the amplifier at LOW current).

	If the motor doesn't need to reverse, a PWM switching
regulator + pass transistor can do a good job.  In the general
case, you might consider buying a computer-controlled stepping
motor for the task (but that doesn't interface nicely with
an op amp feedback circuit...).

	John Whitmore