Electro-Magnetism for AC/DC engines

Tl;DR

Post electro-magnetism 101 and electronics

Intro

Ive been doing additional electronics recaps before going all in with more electronics ideas

git clone /electronics-101/samples-motors

Circuits Recap

Electric Engines

Wondering about buying a car?

DC

AC

Modelling

The L-R

Conclusions

Why all of this?

Well, you can use this knowledge for fpv/drons:

See also this one.

The drone brushless DC motors will have present Faraday law with their Back EMF, same principle of the EMF kickback of the watering project.

$$\nabla \times \mathbf{E} = -\frac{\partial \mathbf{B}}{\partial t}$$

Remember: A changing magnetic field creates an electric field!

Or to understand electric cars before buying one

Total Energy Spent: Approximately 211 kWh. Efficiency: $211\text{ kWh} / 16.3\text{ (units of 100km)} = \mathbf{12.9\text{ kWh/100km}}$.

Note: You actually drove more efficiently than your initial 15 kWh estimate!

Unit Cost Comparison ($ USD per 1 kWh)

FAQ

AC vs DC Power Transmission

As experimented and summarized here:

Converting Electrical Energy

1. Rectifier (AC $\rightarrow$ DC)

A Rectifier converts Alternating Current (AC) into Direct Current (DC).

• How it works: It uses diodes (which act like one-way valves) to block or redirect the “backwards” part of the AC wave so the electricity only flows in one direction.
• Common Example: Your phone charger. It takes the AC from your wall and rectifies it into the DC your battery needs.

2. Inverter (DC $\rightarrow$ AC)

An Inverter converts Direct Current (DC) into Alternating Current (AC).

• How it works: It uses high-speed switches (transistors) to “chop up” the flat DC signal and flip its polarity back and forth to mimic the wave shape of AC.
• Common Example: Solar panels. They produce DC, but your home appliances need AC, so a “Solar Inverter” sits in the middle.

Home pv setups tend to have one of these!

3. Transformer (AC $\rightarrow$ AC)

You are exactly right—a Transformer stays within the same “lane” (AC to AC).

• How it works: It uses magnetic induction to change the voltage and current levels, but it cannot change the nature of the current. It cannot work with DC because it requires a changing magnetic field (which only AC provides).
• Common Example: Those big grey cans on utility poles. They take high-voltage AC from the power lines and “step it down” to the 110V/230V AC used in your house.

Pro Tip: If you want to go from DC to DC (like changing the voltage of a battery), you use something called a DC-DC Converter (often a “Buck” or “Boost” converter).