From: Jon Chandler <jon.chandler@gmail.com>
To: Microcontroller discussion list - Public. <piclist@mit.edu>
Sender: "piclist-bounces@mit.edu" <piclist-bounces@mit.edu>
Date: Thu, 6 Feb 2020 00:01:47 -0800
Subject: Re: [EE] Power transmission
Thread-Topic: [EE] Power transmission
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Could you use a wireless Qi charger as used in cell phones?  Both barebones
senders and receivers are available cheap.

On Tue, Feb 4, 2020, 2:27 PM David Van Horn <
david.vanhorn@backcountryaccess.com> wrote:

> Class E drive?
>
> --
> David VanHorn
> Lead Hardware Engineer
>
> Backcountry Access, Inc.
> 2820 Wilderness Pl, Unit H
> Boulder, CO  80301 USA
> phone: 303-417-1345  x110
> email: david.vanhorn@backcountryaccess.com
>
> -----Original Message-----
> From: piclist-bounces@mit.edu <piclist-bounces@mit.edu> On Behalf Of
> Harold Hallikainen
> Sent: Tuesday, February 4, 2020 2:15 PM
> To: Microcontroller discussion list - Public. <piclist@mit.edu>
> Subject: Re: [EE] Power transmission
>
> True. However, this would reduce efficiency since the FET drain would see
> a sine wave. An interesting approach I've seen in broadcast transmitters =
is
> class F amplifiers where harmonic filters are added between the transisto=
r
> and the output. This is shown, for example, at
>
> https://etd.ohiolink.edu/!etd.send_file?accession=3Dwright1422547511&disp=
osition=3Dinline#page=3D15
> . This allows the transistor to have a square wave (drain voltage zero
> when current high, drain current zero when drain voltage high) while the
> output is a sine wave.
>
> Harold
>
>
> > A high q resonant circuit should help
> >
> > On Tue, Feb 4, 2020, 12:32 PM Harold Hallikainen
> > <harold@mai.hallikainen.org>
> > wrote:
> >
> >> I wonder about radio interference with several watts of 250 kHz
> >> square wave. One nice thing about the Linear Technology designs (at
> >> Analog
> >> Devices) is that they comply with EMC requirements.
> >>
> >> Harold
> >>
> >> > If you want to set up something simple for a test you need a mosfet
> >> > driver, a coil of 20awg or so wire, about 30 turns in a coil about
> >> > 3 inches across, a coil with about 200uh , a 200pf cap and a
> >> > schottky diode.  That is
> >> the
> >> > sending parts and the receiving part is a coil as close to the
> >> > first
> >> 30
> >> > turn coil in size and shape.  I can post more details if interested =
..
> >> This
> >> > will transfer about 3 watts using a frequency of 250khz  over a
> >> distance
> >> > of
> >> > about 1 inch.   Of course you also need a frequency generator with
> >> square
> >> > wave output.    The most important part is the coils, the better the=
 q
> >> the
> >> > more efficient it will be.
> >> >
> >> >
> >> > On Mon, Feb 3, 2020, 5:44 PM Neil <picdude3@narwani.org> wrote:
> >> >
> >> >> I'm tinkering with power transmission for getting power from
> >> >> behind a wall panel to in front.  For now I'm just experimenting
> >> >> with the
> >> idea,
> >> >> but I can't find much info on the relationship between coil
> >> >> diameter, wire diameter, number of turns, frequency, and distance.
> >> >> Anyone here know anything about this?
> >> >>
> >> >> Cheers,
> >> >> -Neil.
> >> >>
> >> >>
> >> >> --
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