# Week 9: Output Devices - Richard Shan, David Vaughn¶

## Assignment¶

For this week, we were assigned to:

• Measure the power consumption of an output device.
• Document your work on the group work page and reflect on your individual page what you learned.

## Servo Power Consumption¶

To calculate the power consumption of a servo motor, we used a multimeter to find the circuit’s voltage and current.

To measure the voltage, we first turned on the servo. We then turned the multimeter to measure in volts and placed the positive probe of the multimeter on the VCC port on the PCB (before the power enters the servo) and the second negative probe of the multimeter on the GND port on the PCB (after the current goes through the servo).

We see that the voltage fluctuates but is generally around 5V. This corroborates the 5V power output of the chip.

We then turned the multimeter to measure Amps for the current. To measure the current, we needed to break the circuit and use the multimeter to connect the two parts. The easiest spot to break the circuit was in the pin connection from the servo to the board. We switched the female to male VCC cable to a male to male cable and taped the cable down so it wouldn’t move during measurement.

We then put the probes of the multimeter on both sides of the previous pin connection and measured the current.

We also added a component on top of the servo before measuring current to emphasize that the multimeter completes the circuit and measures current via allowing the flow of electricity through the multimeter.

Although the current measurement slightly fluctuates, it generally is centered and hovers around 0.1A.

To calculate the overall power consumption in Watts, we used the formula `P = V × A` where P is the power consumption, V is the voltage, and A is the Amps. Thus, `P = 5V × 0.1A` gives us a total power consumption of 0.5 W.

Last update: March 25, 2024