Skip to main content

Power Equation

p=vi,(1.4)
where
p=the power in watts,v=the voltage in volts,i=the current in amperes.
Equation 1.4 shows that the power associated with a basic circuit element is
the product of the current in the element and the voltage across the element.
Therefore, power is a quantity associated with a circuit element, and we have
to determine from our calculation whether power is being delivered to the
circuit element or extracted from it. This information comes from correctly
applying and interpreting the passive sign convention .
If we use the passive sign convention, Eq. 1.4 is correct if the reference
direction for the current is in the direction of the reference voltage drop
across the terminals. Otherwise, Eq. 1.4 must be written with a minus sign. In
other words, if the current reference is in the direction of a reference voltage
rise across the terminals, the expression for the power is
p=−vi.
The algebraic sign of power is based on charge movement through voltage
drops and rises. As positive charges move through a drop in voltage, they
lose energy, and as they move through a rise in voltage, they gain energy.
Figure 1.6 summarizes the relationship between the polarity references for
voltage and current and the expression for power. 
Labels:

Comments

Post a Comment

Popular posts from this blog

How to Play a Sound After a Terminal Command Completes

  Sometimes, while working on the terminal, especially during long-running processes, it’s useful to have an audible notification when the task is finished. In this guide, we’ll show you how to make your terminal play a sound after any command completes, ensuring you're alerted without constantly checking the terminal. Why Do This? This trick can save time and improve workflow, especially when: You’re running lengthy build processes or installations. You’re waiting for large file transfers. You're programming embedded systems and need confirmation when flashing is done. Let’s dive into how to do this on a Linux system. Step-by-Step Guide to Playing a Sound After a Command 1. Using paplay or aplay to Play Sounds On most Linux distributions, you can use paplay or aplay to play sound files directly from the terminal. Here's how you can append a sound notification after a command. Basic Command Structure : PC:~$ your_command && paplay /path/to/soundfile.oga  Or, if...
Post a Comment
Read more

Building a Robot Actuator with ESP32 and a 5010 BLDC Motor

Introduction Modern robotics demands actuators that aren’t just strong, but also smart — capable of precise control, smooth motion, and safe human interaction. Traditional servos are great for small robots, but they can be stiff, noisy, and limited in range or torque. This project demonstrates a custom robot actuator built around a 5010 360 KV brushless DC (BLDC) motor , controlled by an ESP32 running the SimpleFOC library. The goal is to create a compliant joint — one that can be moved by hand, but automatically returns to its home position with adaptive stiffness. 🧠 What Makes This Actuator Special Unlike a typical servo, this actuator behaves intelligently : You can turn it by hand — it feels soft and back-drivable. When you release it, the motor returns to its initial position smoothly. If you twist it harder (e.g., due to gear reduction), it becomes stiffer , resisting displacement more strongly. It’s powered by 12 V and controlled by a simple ESP32 boar...
Post a Comment
Read more

How to Automatically Change Citation Color in Word (e.g., Blue) Using Zotero + Macro

  Hi everyone 👋 I’ll be honest upfront: I’m not a huge fan of Microsoft Word — I usually work in LaTeX , where formatting and citations behave exactly the way I want without any hacks 😄 That said, we all occasionally find ourselves back in Word , whether for collaborations, journal templates, or institutional requirements. And when that happens, a few quirky tricks can go a long way. If you’re using Zotero with Microsoft Word and want to improve the visual style of your document, this small trick can be surprisingly useful. In many scientific papers and technical documents, in-text citations appear in blue , similar to hyperlinks. Unfortunately, Zotero does not provide a built-in option to automatically change citation colors in Word. The good news? You can achieve this easily using a simple Word VBA macro  no need to abandon Zotero or manually format citations one by one. i originally found this in zotero forms this >  Post  < Below is a simple,...
Post a Comment
Read more