Re: W2 review - and why the diode...

Posted by Richard Squire - HB9ANM on
URL: http://elecraft.85.s1.nabble.com/W2-tp4000196p4014449.html

Hello David

Why the diode? Well, any relay driven by a solid-state device should have a diode across its coil (in reverse polarity!) to short reverse voltage spikes. Transistor are rather fast switches... and such spikes would damage them. Never drive a relay from a transistor or IC without such a parallel diode!
73
Richard - HB9ANM

David Ferrington, M0XDF wrote

Now that's a good idea. Why the diode?
73 de M0XDF, K3 #174
--  
The soul is the same in all living creatures, although the body is
different. -Hippocrates, physician (460-c.377 BCE)

On 14 Nov 2009, at 08:31, AD6XY wrote:

> My K3 12V output powers an automotive relay (+diode) which connects  
> the 12V
> PSU to an 8 way powerpole panel. This allows me to control the power  
> to the
> LP-100A, the transverters, the KRC2 and an AT-1000pro with the K3  
> power
> switch.

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