[GreenKeys] Basic Loop supply
epvgk at limpoc.com
epvgk at limpoc.com
Wed May 18 13:52:24 EDT 2016
On Wed, May 18, 2016 at 01:39:55PM -0400, Lester Veenstra wrote:
>
> The pricey item is the variable wire wound resistor
>
> It may be possible to replace this with a fast opto isolated MOSFET with a
> pulse width modulated drive instead if a high enough witching rate can be
> used.
>
It also doesn't have to be adjustable from 0 to 2.5K - for example you can
use a high wattage fixed resistor like
http://www.digikey.com/product-detail/en/riedon/UAL10-2KF8/696-1492-ND/3886624
or http://www.digikey.com/product-detail/en/yageo/SQP10AJB-2K0/2.0KW-10-ND/18789
in series with a smaller variable resistor which at 500 ohms would dissipate
no more than 1.5W at 60mA. May not provide sufficient adjustment range, but
it could at least offload the expensive part of the job to a cheaper fixed resistor.
eric
>
>
>
>
> Lester B Veenstra M?YCM K1YCM W8YCM
>
> lester at veenstras.com
>
>
>
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>
> From: GreenKeys [mailto:greenkeys-bounces at mailman.qth.net] On Behalf Of Paul
> Birkel
> Sent: Tuesday, May 17, 2016 6:38 PM
> To: 'Lester Veenstra'; COURYHOUSE at aol.com; epvgk at limpoc.com;
> greenkeys at mailman.qth.net
> Subject: Re: [GreenKeys] any missing USB-tty adapter orders?
>
>
>
> How would that work? Let?s see that design :->!
>
>
>
> From: GreenKeys [mailto:greenkeys-bounces at mailman.qth.net] On Behalf Of
> Lester Veenstra
> Sent: Tuesday, May 17, 2016 6:14 PM
> To: COURYHOUSE at aol.com; epvgk at limpoc.com; greenkeys at mailman.qth.net
> Subject: Re: [GreenKeys] any missing USB-tty adapter orders?
>
>
>
> This could be done if someone as a stash of low cost variable ww resistors
> of about 1.5 K Ohms and 12.5 watts capacity.
>
>
>
> Lester B Veenstra M?YCM K1YCM W8YCM
>
> lester at veenstras.com
>
>
>
> Physical and US Postal Addresses
>
> 5 Shrine Club Drive (Physical)
>
> 452 Stable Ln (RFD USPS Mail)
>
> Keyser WV 26726
>
> GPS: 39.336826 N 78.982287 W (Google)
>
> GPS: 39.33682 N 78.9823741 W (GPSDO)
>
>
>
>
>
> Telephones:
>
> Home: +1-304-289-6057
>
> US cell +1-304-790-9192
>
> UK cell +44-(0)7849-248-749
>
> Guam Cell: +1-671-929-8141
>
> Jamaica: +1-876-456-8898
>
>
>
> This e-mail and any documents attached hereto contain confidential or
> privileged information. The information is intended to be for use only by
> the individual or entity to whom they are addressed. If you are not the
> intended recipient or the person responsible for delivering the e-mail to
> the intended recipient, be aware that any disclosure, copying, distribution
> or use of the contents of this e-mail or any documents attached hereto is
> prohibited.
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>
>
> From: COURYHOUSE at aol.com [mailto:COURYHOUSE at aol.com]
> Sent: Tuesday, May 17, 2016 5:36 PM
> To: m0ycm at veenstras.com; epvgk at limpoc.com; greenkeys at mailman.qth.net
> Subject: Re: [GreenKeys] any missing USB-tty adapter orders?
>
>
>
> what we need now is the one board 60 mil voltage source small
> and cheap! assembled...
>
>
>
> seriously will all the stuff I need to do ion a days and nights time I
> really do not have that much time to build things,....
>
>
>
> Eric's boards were an answer to a long uttered prayer!
>
>
>
> the next thing that would be cool is one with wireless network interface
> on it and sms? well maybe at least the wireless network.
>
>
>
> for 80 percent of what I am doing these usb boards with the push
> button to type message fill the bill.
>
>
>
>
>
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>
>
>
>
> In a message dated 5/17/2016 2:27:10 P.M. US Mountain Standard Time,
> m0ycm at veenstras.com writes:
>
> Who knew? Well, all of us, who planned to do something similar but "never
> got around to actually doing it!"
> Well done
> Les
>
> Lester B Veenstra M?YCM K1YCM W8YCM
> lester at veenstras.com
>
> Physical and US Postal Addresses
> 5 Shrine Club Drive (Physical)
> 452 Stable Ln (RFD USPS Mail)
> Keyser WV 26726
> GPS: 39.336826 N 78.982287 W (Google)
> GPS: 39.33682 N 78.9823741 W (GPSDO)
>
>
> Telephones:
> Home: +1-304-289-6057
> US cell +1-304-790-9192
> UK cell +44-(0)7849-248-749
> Guam Cell: +1-671-929-8141
> Jamaica: +1-876-456-8898
>
> This e-mail and any documents attached hereto contain confidential or
> privileged information. The information is intended to be for use only by
> the individual or entity to whom they are addressed. If you are not the
> intended recipient or the person responsible for delivering the e-mail to
> the intended recipient, be aware that any disclosure, copying, distribution
> or use of the contents of this e-mail or any documents attached hereto is
> prohibited.
>
> -----Original Message-----
> From: GreenKeys [mailto:greenkeys-bounces at mailman.qth.net] On Behalf Of
> epvgk at limpoc.com
> Sent: Tuesday, May 17, 2016 1:34 PM
> To: greenkeys at mailman.qth.net
> Subject: [GreenKeys] any missing USB-tty adapter orders?
>
> Hi --
>
> Just wanted to check whether anyone who ordered a cl adapter hasn't gotten
> it yet. Haven't heard any reports of lost ones but I don't want anyone
> sitting around waiting two weeks for something that should take 3 days. :)
>
> btw 69 of them have gone out so far - who knew!
>
> eric
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