Using a 2ch scope as a short period timer

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I want to measure the reaction, or turn on time between two short period events.

Power on goes instantly from 0Volts to 12Vdc. probe 1 of scope will show the DC as a flat line after turn on.

A timer starts a delay and then changes state (output voltage). The output voltage changes from 12Vdc to 0.1Vdc. probe 2 of scope will show this as a flat line @ 100mVdc.

Is there a way to trigger the scope on the first event (power On) 0V to 12V and see the delay in the horizontal trace of the second event (timer expired) to show when the voltage changed after the delay period?

If this were a regularly repeated string of dozens of On/Off events, the trace would look like a pair of very long period square waves.
But for a single event the two traces would flash up on screen and be lost in the flat lines that follow.

Any ideas about how to trigger an analogue scope to show the delay/interval?
 
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Unless you have a storage scope of some sort, looking at single shot events on an analog scope is nigh impossible. You might be able to get by with taking some sort of long exposure photo, but that will be your ONLY option. Non-storage analogue scopes are not designed to do what you want. This is why storage scopes were invented.

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  • Set the timebase mode to "Trigger" (usually, it's on "Auto")
  • Select Ch1 as trigger source, DC coupling, positive transition
  • Display only CH2 with a suitable scale, make the 0.1V level coincide with the center of the graticule (make your trace and sensitivity adjustments in Auto mode).
  • Adjust the H position to make the trace begin coincide with the left side of the graticule.
  • Adjust the timebase according of the expected duration of the timer: eg. 200ms/div for up to 2s.
Fire the supply: you will see the trace come back to the center of the graticule as soon as the time is up, and it will be easy to memorize the exact position on the graticule, even without memory or persistent phosphor
 
  • Set the timebase mode to "Trigger" (usually, it's on "Auto")
  • Select Ch1 as trigger source, DC coupling, positive transition
  • Display only CH2 with a suitable scale, make the 0.1V level coincide with the center of the graticule (make your trace and sensitivity adjustments in Auto mode).
  • Adjust the H position to make the trace begin coincide with the left side of the graticule.
  • Adjust the timebase according of the expected duration of the timer: eg. 200ms/div for up to 2s.
Fire the supply: you will see the trace come back to the center of the graticule as soon as the time is up, and it will be easy to memorize the exact position on the graticule, even without memory or persistent phosphor
I'll give that a try.
Thanks.
 
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Analogue scope... I would try and use the tubes persistence tbh.

A darkened room with the brightness up and a slow time base speed should leave a bright trail for a moment and so enable a good estimate of the delay to be read from the trace.

Another more involved method. Record the two traces as an audio signal and then look at the waveform in Audacity. You would see the clicks and should be 100% accurate.
 
..............Another more involved method. Record the two traces as an audio signal and then look at the waveform in Audacity. You would see the clicks and should be 100% accurate.
I am getting ready to buy a second Win7 license and do a clean install on my second PC.
That would be located in my electronics room/workshop upstairs.
Audacity, or something similar will come along then.
Thanks.
 
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Sounds like a plan.

(W7 has a large following, but slowly and surely it is going to become unsupported. Have you thought about investigating in W10. If you have a spare PC then you can try it for free for 90 days. You can also permanently get it for free from a valid W7 license... just a thought, you might actually like it)
 
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