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Re: [Amps] Checking relay timing with a scope

To: Amps reflector <>
Subject: Re: [Amps] Checking relay timing with a scope
From: "Bill, W6WRT" <>
Date: Sun, 21 Jun 2009 08:28:30 -0700
List-post: <">>

On Sun, 21 Jun 2009 11:14:33 -0400, Pete Smith <>

>It is dual trace, and it has choice of internal or external triggering.
>73, Pete N4ZR


Ok, the best way to observe relay closure is to temporarily wire a DC
source to each relay's armature (the movable wiper) and connect the
output of each relay to one channel of the dual trace scope. Set the
scope to 'chopped' sweep. Chopped sweep allows you to observe both
relays in real time, as opposed to 'alternare' sweep, which would not
be useful in this application. Set both vertical channels and the
trigger channel to 'DC' coupling. If 'AC' coupling were used it might
confuse the results a little.

Connect the relay coil to the external trigger input so that when the
relay coil is activated, the sweep begins. Set the sweep rate to about
5 milliseconds per division. 

Now when the relay coil is activated, the sweep will start and when
the relay contacts close, the DC signal will appear on each trace and
you can measure both the delay between coil energizing and relay
closure, and any difference between the closure of the two relays. 

This usually takes a little experimenting to get the trigger level
correct and also the vertical sensitivity and trace position correct.

Make sense?

73, Bill W6WRT
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