Difference between revisions of "Linear Amplifier Motor Driver"

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[[image:linear amplifier schematic.jpg|500px]]
[[image:linear amplifier schematic.jpg|500px]]


This is a very simple linear amplifier. A better linear amplifier, and the associated board available for stuffing in the NU mechatronics lab, is described [http://www.mech.northwestern.edu/courses/433/Writeups/MotorAmp/motoramp.htm here].
One of the problems with this circuit is that it isn't very efficient. Lots of power is dumped into ground and into heat. Large heatsinks are required for the transistors even when using small motors. For a more efficient method, consult [[Pulse Width Modulation]].

While a linear amplifier can work very well, they are not very power efficient. Lots of power is dumped into heat. Large heatsinks may be required for the transistors even when using small motors. For a more power-efficient method of driving motors, which also has the benefit that only on-off voltages are required, consult [[Pulse Width Modulation]].

Revision as of 18:20, 20 October 2006

A simple driver for a motor is a "push-pull" current amplifier. This circuit uses two transistors to "push" or "pull" current through the motor. The transistors are npn-type and are activated by an applied voltage. The op-amp linearizes the circuit and provides a current gain. The input is an analog voltage.

Linear amplifier schematic.jpg

This is a very simple linear amplifier. A better linear amplifier, and the associated board available for stuffing in the NU mechatronics lab, is described here.

While a linear amplifier can work very well, they are not very power efficient. Lots of power is dumped into heat. Large heatsinks may be required for the transistors even when using small motors. For a more power-efficient method of driving motors, which also has the benefit that only on-off voltages are required, consult Pulse Width Modulation.