Request expert opinion on this wireless cellphone charger circuit

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Could some electronics guru please provide his/her opinion
on this supposed wireless cellphone charger circuit at the  
following URL:

http://www.homemade-circuits.com/2015/09/wireless-cellphone-charger-circuit.html

What puzzles me is that how could an oscillator be set up with
just a 2N2222 BJT and a 220 Ohm resistor, without any information
on the inductances(antenna). I await your opinions.

Re: Request expert opinion on this wireless cellphone charger circuit
On 11/25/2015 8:06 PM, snipped-for-privacy@gmail.com wrote:
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it's a transformer

Re: Request expert opinion on this wireless cellphone charger circuit
On 26/11/2015 04:57, mike wrote:
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Notice how the center-tap is connected to +ve supply. It is also a  
Hartley oscillator (look it up if you want) tuned by the  
self-capacitance of the spiral inductors and the reflected capacitance  
of whatever receiver coil and attached circuitry is nearby. The  
frequency of oscillation will vary as the whole setup is moved.

It creates electro-magnetic pollution and will seriously annoy anyone  
nearby using AM BC or SW receivers.

piglet


Re: Request expert opinion on this wireless cellphone charger circuit
On Wed, 25 Nov 2015 20:06:28 -0800 (PST), snipped-for-privacy@gmail.com wrote:

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Most respondents seem to be having issues (burnt switches), and the
blogger admits that he hasn't actually done it himself with the
described hardware. Oscillators operating on the principal of bipolar
transistor base current starvation will be inefficient, and are best
reserved for small-signal applications, where the losses are not
signifigant.

References in the blog are made to a you-tube video, which shows a
much larger heatsunk switch, and a maximum power transmission
efficiency of less than 50%, based on the actual DC load measurements
made there.

'Examining Wireless Power Transfer' TI SEM1200 topic3 slup321:

http://www.ti.com/lit/pdf/slup321

RL

Re: Request expert opinion on this wireless cellphone charger circuit
snipped-for-privacy@gmail.com says...
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its a dangerous circuit...

The 2222 is rated for 800mA last time I looked, and that should
be attached to a sink. Wattage is a factor.

 There should be a regulator in there to supply the phone, I would not
be putting wild voltages to the phone.

 Jamie


Re: Request expert opinion on this wireless cellphone charger circuit
On Fri, 27 Nov 2015 16:00:11 -0500, M Philbrook

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The phone's battery is a simple shunt regulator to the
impedance-limited source.

RL


Re: Request expert opinion on this wireless cellphone charger circuit

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Good luck getting it through Part 15 as an intentional radiator.


Re: Request expert opinion on this wireless cellphone charger circuit
On Fri, 27 Nov 2015 18:27:56 -0500, "Tom Miller"

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I think you might mean "unintentional" radiator for external battery
chargers.  See:
<http://www.ecfr.gov/cgi-bin/text-idx?SID95%ff763337f596a0ff6da3ef78b56380&node=se47.1.15_1101&rgn=div8
Note that for a "Class B external switching power supplies", the tests
are only for "verification", which means the FCC trusts the
manufacturer to be honest, competent, and trustworthy.  Right.

--  
Jeff Liebermann     snipped-for-privacy@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
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Re: Request expert opinion on this wireless cellphone charger circuit

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I think the external battery chargers referred to here are just line powered  
switching supply bricks. It could be covered under "any other device"  
though. But it does intentionally radiate a RF field. And it's anybody's  
guess as to the frequency.

"honest, competent, and trustworthy"  especially in China.



Re: Request expert opinion on this wireless cellphone charger circuit
On Fri, 27 Nov 2015 21:27:17 -0500, "Tom Miller"

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Intentional radiators are those that are intentionally designed to
communicate with some other device.  Unintentional radiators are those
that belch RFI/EMI without a designated receiving device.  I'm quite
sure that a switching power supply is not intended to send useful
voice, video, or data to a receiver, and is therefore an unintentional
radiator.  

You'll find the definitions under:
<http://www.ecfr.gov/cgi-bin/retrieveECFR?gp=&SID55%1cee4848a4b3cfb33ca2ec0292ef14&mc=true&n=pt47.1.15&r=PART&ty=HTML#se47.1.15_13

(o) Intentional radiator. A device that intentionally generates and
emits radio frequency energy by radiation or induction.

(z) Unintentional radiator. A device that intentionally generates
radio frequency energy for use within the device, or that sends radio
frequency signals by conduction to associated equipment via connecting
wiring, but which is not intended to emit RF energy by radiation or
induction.

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Ummm.... I was trying to be diplomatic and subtle.

--  
Jeff Liebermann     snipped-for-privacy@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
We've slightly trimmed the long signature. Click to see the full one.
Re: Request expert opinion on this wireless cellphone charger circuit
snipped-for-privacy@nospam.magma.ca says...
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 Yeah? what about the circuits you need to go through before  
getting to that battery?

 Think.

Jamie


Re: Request expert opinion on this wireless cellphone charger circuit
On Wednesday, November 25, 2015 at 11:06:36 PM UTC-5, snipped-for-privacy@gmail.com wro
te:
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it.html

It's not an oscillator, it's a short circuit on the 12V source, limited onl
y by transistor beta. The DC path through the transformer to the base locks
 the circuit up (with 60mA base drive which is a LOT), it will not oscillat
e. This type of circuit requires ac-coupled feedback to work.

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