Mechatronics, Industrial Control & Instrumentation

DC Motor Power Op-amp Speed Controller

Let’s consider the functional diagram below:

DC motor power op-amp speed controller functional diagram
Figure 1 DC motor power op-amp speed controller functional diagram

The D/A converter outputs a voltage directly related to the potentiometer position. However, the D/A converter’s output current is limited and not enough to drive a motor.  A power operational amplifier (op-amp) circuit, configured as a noninverting amplifier can drive the motor at the higher currents required. In effect, the power amp will serve as a buffer between the D/A converter and the motor.

The circuit below shows the components used along with their interconnections.

Figure 2 Circuit showing op-amp (OPA 547) between the D/A converter and the dc motor

The OPA 547 can be powered by a bipolar (±) 9 V supply instead of a standard bipolar 15 V supply. With an input resistor of 10 kꭥ and a feedback resistor of 1 kꭥ, the power amp circuit has a gain of 1.1, therefore, the voltage from the D/A converter is not amplified a lot, but the circuit is able to source ample current to the dc motor.

You can also read: Pulse Width Modulation (PWM) Speed Control of a DC motor

John Mulindi

John Mulindi is an Industrial Instrumentation and Control Professional with a wide range of experience in electrical and electronics, process measurement, control systems and automation. In free time he spends time reading, taking adventure walks and watching football.

Recent Posts

Standard Process Signals for Industrial Instrumentation

Industrial measurement and control processes employ standard process signals that are used throughout all the…

1 week ago

Top 5 Benefits of Combining CCTV Cameras with Biometric Systems

The integration of advanced technologies in security systems has become imperative for ensuring safety and…

1 week ago

Sources of Power Quality Problems

Power quality may be affected by a number of issues. Our discussion in this article…

2 weeks ago

Common Terms Used When Describing Power Quality Problems

Power quality has become an important issue to electricity consumers at all levels of consumption.…

2 weeks ago

What to Expect from PCB Assembly Services in China

The importance of printed circuit board (PCB) technology has escalated throughout the years with the…

2 weeks ago

Magneto-Optic Current Sensors for High Voltage, High Power Transmission Lines

One of the key challenges in measuring the electrical current in high voltage, high power…

3 weeks ago