Linear Amplifier Motor Driver

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Revision as of 17:20, 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.

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