Towertalk
[Top] [All Lists]

Re: [TowerTalk] Protection of a preamp

To: "Lizeth Norman" <normanlizeth@gmail.com>, "towertalk" <towertalk@contesting.com>
Subject: Re: [TowerTalk] Protection of a preamp
From: "Patrick Greenlee" <patrick_g@windstream.net>
Date: Tue, 21 Jan 2014 10:25:08 -0600
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Well that is one way. Another is to use a (one, 1 , ein un) Zener diode to subtract out the difference. Another way is to measure the current draw of the amps when operated on proper voltage and then calculate the value of a series resistor required to drop the excess voltage at that current.

For your convenience: I=E/R P=IE (don't forget to calc the power dissipated by the R so you can size it (them if you use more than one.)

A cap across the power connections at the amps won't hurt but probably not THAT BIG.

Patrick NJ5G


-----Original Message----- From: Lizeth Norman
Sent: Tuesday, January 21, 2014 10:14 AM
To: towertalk
Subject: [TowerTalk] Protection of a preamp

Hi all!
I have a preamp that I switch in and out with a pair of spdt coaxial
relays. The NC positions pass through and the NO positions hold the preamp.
The relays are +24Vdc and the preamp needs ideally 12Vdc.
Presently, I have the preamps hooked up to +24Vdc and they are frying.
What I'd like to do is when I key the relay, also feed the preamp through
20 diodes to drop the Voltage to something respectable. Possibly using a
100uF cap across the preamp.
Am I asking for trouble? Do dragons live here?
Norm n3ykf
_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk

<Prev in Thread] Current Thread [Next in Thread>