[Elecraft] K2 Muting

[Jack Brindle]

Ack! You sure you want to do this, Don? Pin 17 is bipolar drive, so you 
would be shorting a relatively high-current output (25 mA per spec)  to 
ground. That has a good potential for letting smoke out of the MCU.

IF you do this, I HIGHLY recommend a current limiting protection 
resistor in the circuit. A few hundred ohms should do, but might also 
affect muting operation...

On Dec 9, 2004, at 10:41 AM, W3FPR - Don Wilhelm wrote:

> For something more temporary, an open collector transistor connected 
> to pin 17 of the MCU (Control Board U6) would do the job for you - 
> drive the base of the transistor with 3 to 5 volts to turn it on when 
> you want the K2 muted.  A 2N2222 or similar should work just fine.

-Jack Brindle, W6FB
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