[Elecraft] Silly question - what is KEY OUT?

[Don Wilhelm]

Yes - and it is an output because it is the K3 that making a condition 
available (switch closure) to the outside world.  An input is something 
coming from the outside world that would control the K3.  The K3 'sends' 
either an open circuit or a conducting condition - it is a HEXFET 
driving this output - no relays are used in the K3 T/R switching or keying.

I am puzzled about why you would want to connect your code practice 
oscillator to this output.  If you want code practice, just put the K3 
into TX TEST and you will hear sidetone from the K3 as you key it - no 
need for the external oscillator - but of course, if you 'just want to 
do it', then by all means go ahead with it.

73,
Don W3FPR

Darwin, Keith wrote:
> Yea, I knooooww, but I'm a SW person so I sometimes get lost in the EE
> details, even when they are very basic.
>
> By "T-R Relay keying output" I guess it means it is a relay that can be
> used to control the T/R switching of an external amp.  In other words,
> the KEY OUT jack acts like a switch, open / closed.  The Amp would have
> a TR line that would be providing a voltage.  When the K3 KEY OUT goes
> to "closed", the Amplifier's TR line would be pulled to ground and this
> would tell the amp to switch to TX.  Yes?
>
> The fact it is labeled as an output confuses me a bit, making me think
> the K3 is sending some voltage, but the K3 sending 1KW (200 v @ 5 amps)
> makes no sense.
>
> I'm just hoping it can be used to make my old Heathkit code oscillator
> beep when I send CW with the K3.  
>
> Or maybe I can use it to turn my coffee pot on :-)
>
> - Keith N1AS -
> - K3 711 -
>
> -----Original Message-----
> From: Don Wilhelm [mailto:w3fpr at embarqmail.com] 
>
>  From page 17 of the manual
> "KEY OUT (RCA/Phono) is the amplifier T-R relay keying output, capable
> of keying up to +200VDC @ 5A."
>
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