[Elecraft] K4 Key Out spec

[Bob Wilson, N6TV]

Though not in the K4 manuals, the K4 KEY OUT jack (an RCA phono connector)
has the same specs as the K3 KEY OUT jack: capable of keying up to +200VDC
@ 5A.  The K4 uses the same MOSFET as the K3, an IRFI630 (see datasheet
<https://www.mouser.com/datasheet/2/427/91148-1768921.pdf>).

Note that the *other* key out line, PIN 8 on the ACC connector, is rated
for 10 mA max, which is also the same as the K3.  If you want to know how
much current  your amplifier KEY IN (relay) jack requires,  short an
ammeter across the KEY IN jack, negative lead to ground.  This should key
the amplifier relay, and then you can read the current.  Usually it's way
under 10 ma.

73,
Bob, N6TV


On Sun, Jul 4, 2021 at 10:51 AM <cw4ever4 at juno.com> wrote:

> Hello
>       I need  the voltage and current ratings on the K4 Key Out
> interface.   Have a home brew amp that might be exceeding the  K4
> switching device ratings.  And I don't want to let the smoke out. Hi   73
>  Bob  W1XP
>
>
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