[Milsurplus] Dear Smart People: RS-232 Com 1

[hwhall at compuserve.com]

I bet the ansswer depends a lot on the relay. There's are some really sensitive ones.

WayneWB4OGM

-----Original Message-----
From: Al Klase <ark at ar88.net>
To: milsurplus <milsurplus at mailman.qth.net>
Sent: Sat, Feb 8, 2020 12:56 pm
Subject: Re: [Milsurplus] Dear Smart People: RS-232 Com 1

 Hi Dave,
 
 I don't know about traditional relays, but even the RS-232 USB dongles will happily drive a solid-state relay like THIS.
 (Fairchild product, you can buy them onesy-twosy from Mouser if you prefer.)  Input is an LED, so observe polarity and use a 1K series resistor.  Output is high voltage MOSFET's.  Will switch AC or DC.  They can be wired either in series or parallel depending upon the load..
 
 I've used these to key tube-type transmitters and TTY's.
 
 Al
 
 
 On 2/8/2020 1:12 PM, David Stinson wrote:
  
Hello, all you folks smarter than me, especially on computers. 
 Can the common RS-232 Com Port's DTR and RTS lines 
 source enough current to pull-in a small 5V relay? 
 
 Thanks! 
 
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Al Klase – N3FRQ
Jersey City, NJ
http://www.skywaves.ar88.net/
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