[GreenKeys] GreenKeys Digest, Vol 91, Issue 74 mailman.qth.net

I wish I could remember, David. I think it had to do with how fast the contacts snapped open and closed, and I remember somebody saying something about arcing cleaning the contacts. But it was so long ago, so I could be wrong.

Paul
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On Aug 6, 2023, at 7:37 AM, David V. Corbin <[email protected]> wrote:



Paul, trying to wrap my head around this. Ohms law. If the state is static, then to keep a 60mA flow, the voltage will be a constant based on the resistance of the loop. Now when the state transitions to “open” it does not matter how high the voltage goes, there will not be current. Now when the circuit initially closes, inductance May raise the voltage needed for achieving the target current, but then it will lower to the steady state value.

This is why I use programmable current supplies rather than supplies where one sets the voltage. 

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From: [email protected] <[email protected]> on behalf of Paul Heller <[email protected]>
Sent: Sunday, August 6, 2023 9:30:50 AM
To: Jeffrey Golas <[email protected]>
Cc: Gerry Block <[email protected]>; Greenkeys <[email protected]>
Subject: Re: [GreenKeys] Model 14 keyboard adjustment

 

I remember a discussion years ago where a number of folks said high voltage was important for the contacts. The design voltage was much higher than 15v. You might try a loop source that delivers higher voltage and 60ma. That might work better with your contacts. 

Paul
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