[mircemk] has been working on wireless power transmission. Using a Class-E Tesla coil with 12 turns on the primary and 8 turns on the secondary and a 12 volt input he can send a few milliwatts to power an LED over a distance of more than 40 centimeters or power a 10 watt bulb over a distance of about 10 centimeters. With the DC input set at 24 volts the apparatus can deliver 5 watts over a distance of a few centimeters and a light is still visible after separating the primary and secondary coils by more than 30 centimeters.
There are many types of Tesla coil and we can’t go into the details here but they include Spark-Gap Tesla Coils (SGTC) and Solid-State Tesla Coils (SSTC), among others. The Class-E coil demonstrated in this project is a type of SSTC which in general is more efficient than an SGTC alternative.
Please bear in mind that while it is perfectly safe to watch a YouTube video of a person demonstrating a functional Tesla coil, building your own is hazardous and probably not a good idea unless you really understand what you’re doing! Particularly high voltages can be involved and EMI/RFI emissions can violate regulations. You can damage your body with RF burns while not feeling any pain, and without even knowing that it’s happening.
If you’d like to read more about wireless power transmission it is certainly a topic we’ve covered here at Hackaday in the past, you might like to check out Wireless Power Makes For Cable-Free Desk or Transmitting Wireless Power Over Longer Distances.
IMHO, that’s not a Tesla coil. That’s an oscillator driving an air-core transfomer. I don’t see a resonant secondary providing high voltage RF.
Besides the air-cap, I don’t see any filter elements. That thing’s gotta be loud. I wonder how many orders of harmonics it puts out.
I’m guessing all of them…
It’s pretty much a spark gap transmitter. And illegal.
Not to mention the clulessness of the article author. Nobody cares about the voltage. It’s the power delivered to the primary vs the secondary that matters.
Kudos to the builder. Class E is fun. I’ve built a 500 watt rf deck on 10 meters class e, amongst other high power class e peojects.
The great irony of wireless power transmission is that it requires orders of magnitude more wire for the same transmission distance.
Lol. Absolutely hilarious
And now you understand why proposals like “embed inductive charging coils in highways to charge EVs while they’re moving” are practically impossible.
It takes thousands and thousands of miles of copper wire for every mile of road you build.
Imagine the amount of power it would waste too. There would have to be a large gap to have enough ground clearance which reduces the already poor efficiency of wireless charging.